xref: /external/chromium_org/third_party/WebKit/Source/core/frame/FrameView.cpp

/*
 * Copyright (C) 1998, 1999 Torben Weis <weis (at) kde.org>
 *                     1999 Lars Knoll <knoll (at) kde.org>
 *                     1999 Antti Koivisto <koivisto (at) kde.org>
 *                     2000 Dirk Mueller <mueller (at) kde.org>
 * Copyright (C) 2004, 2005, 2006, 2007, 2008 Apple Inc. All rights reserved.
 *           (C) 2006 Graham Dennis (graham.dennis (at) gmail.com)
 *           (C) 2006 Alexey Proskuryakov (ap (at) nypop.com)
 * Copyright (C) 2009 Google Inc. All rights reserved.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public License
 * along with this library; see the file COPYING.LIB.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA 02110-1301, USA.
 */

#include "config.h"
#include "core/frame/FrameView.h"

#include "core/HTMLNames.h"
#include "core/accessibility/AXObjectCache.h"
#include "core/css/FontFaceSet.h"
#include "core/css/resolver/StyleResolver.h"
#include "core/dom/DocumentMarkerController.h"
#include "core/dom/ScriptForbiddenScope.h"
#include "core/editing/FrameSelection.h"
#include "core/events/OverflowEvent.h"
#include "core/fetch/ResourceFetcher.h"
#include "core/fetch/ResourceLoadPriorityOptimizer.h"
#include "core/frame/FrameHost.h"
#include "core/frame/LocalFrame.h"
#include "core/frame/Settings.h"
#include "core/html/HTMLFrameElement.h"
#include "core/html/HTMLPlugInElement.h"
#include "core/html/parser/TextResourceDecoder.h"
#include "core/inspector/InspectorInstrumentation.h"
#include "core/inspector/InspectorTraceEvents.h"
#include "core/loader/FrameLoader.h"
#include "core/loader/FrameLoaderClient.h"
#include "core/page/Chrome.h"
#include "core/page/ChromeClient.h"
#include "core/page/EventHandler.h"
#include "core/page/FocusController.h"
#include "core/page/FrameTree.h"
#include "core/page/scrolling/ScrollingCoordinator.h"
#include "core/rendering/FastTextAutosizer.h"
#include "core/rendering/RenderCounter.h"
#include "core/rendering/RenderEmbeddedObject.h"
#include "core/rendering/RenderLayer.h"
#include "core/rendering/RenderListBox.h"
#include "core/rendering/RenderPart.h"
#include "core/rendering/RenderScrollbar.h"
#include "core/rendering/RenderScrollbarPart.h"
#include "core/rendering/RenderTheme.h"
#include "core/rendering/RenderView.h"
#include "core/rendering/RenderWidget.h"
#include "core/rendering/TextAutosizer.h"
#include "core/rendering/compositing/CompositedLayerMapping.h"
#include "core/rendering/compositing/RenderLayerCompositor.h"
#include "core/rendering/style/RenderStyle.h"
#include "core/rendering/svg/RenderSVGRoot.h"
#include "core/svg/SVGDocumentExtensions.h"
#include "core/svg/SVGSVGElement.h"
#include "platform/RuntimeEnabledFeatures.h"
#include "platform/TraceEvent.h"
#include "platform/fonts/FontCache.h"
#include "platform/geometry/FloatRect.h"
#include "platform/graphics/GraphicsContext.h"
#include "platform/graphics/GraphicsLayerDebugInfo.h"
#include "platform/scroll/ScrollAnimator.h"
#include "platform/scroll/ScrollbarTheme.h"
#include "platform/text/TextStream.h"
#include "wtf/CurrentTime.h"
#include "wtf/TemporaryChange.h"

namespace WebCore {

using namespace HTMLNames;

double FrameView::s_currentFrameTimeStamp = 0.0;
bool FrameView::s_inPaintContents = false;

// The maximum number of updateWidgets iterations that should be done before returning.
static const unsigned maxUpdateWidgetsIterations = 2;
static const double resourcePriorityUpdateDelayAfterScroll = 0.250;

static RenderLayer::UpdateLayerPositionsFlags updateLayerPositionFlags(RenderLayer* layer, bool isRelayoutingSubtree, bool didFullPaintInvalidation)
{
    RenderLayer::UpdateLayerPositionsFlags flags = didFullPaintInvalidation ? RenderLayer::NeedsFullRepaintInBacking : RenderLayer::CheckForRepaint;

    if (isRelayoutingSubtree && (layer->isPaginated() || layer->enclosingPaginationLayer()))
        flags |= RenderLayer::UpdatePagination;

    return flags;
}

FrameView::FrameView(LocalFrame* frame)
    : m_frame(frame)
    , m_canHaveScrollbars(true)
    , m_slowRepaintObjectCount(0)
    , m_hasPendingLayout(false)
    , m_layoutSubtreeRoot(0)
    , m_inSynchronousPostLayout(false)
    , m_postLayoutTasksTimer(this, &FrameView::postLayoutTimerFired)
    , m_updateWidgetsTimer(this, &FrameView::updateWidgetsTimerFired)
    , m_isTransparent(false)
    , m_baseBackgroundColor(Color::white)
    , m_mediaType("screen")
    , m_overflowStatusDirty(true)
    , m_viewportRenderer(0)
    , m_wasScrolledByUser(false)
    , m_inProgrammaticScroll(false)
    , m_safeToPropagateScrollToParent(true)
    , m_isTrackingPaintInvalidations(false)
    , m_scrollCorner(0)
    , m_shouldAutoSize(false)
    , m_inAutoSize(false)
    , m_didRunAutosize(false)
    , m_hasSoftwareFilters(false)
    , m_visibleContentScaleFactor(1)
    , m_inputEventsScaleFactorForEmulation(1)
    , m_layoutSizeFixedToFrameSize(true)
    , m_didScrollTimer(this, &FrameView::didScrollTimerFired)
{
    ASSERT(m_frame);
    init();

    if (!m_frame->isMainFrame())
        return;

    ScrollableArea::setVerticalScrollElasticity(ScrollElasticityAllowed);
    ScrollableArea::setHorizontalScrollElasticity(ScrollElasticityAllowed);
}

PassRefPtr<FrameView> FrameView::create(LocalFrame* frame)
{
    RefPtr<FrameView> view = adoptRef(new FrameView(frame));
    view->show();
    return view.release();
}

PassRefPtr<FrameView> FrameView::create(LocalFrame* frame, const IntSize& initialSize)
{
    RefPtr<FrameView> view = adoptRef(new FrameView(frame));
    view->Widget::setFrameRect(IntRect(view->location(), initialSize));
    view->setLayoutSizeInternal(initialSize);

    view->show();
    return view.release();
}

FrameView::~FrameView()
{
    if (m_postLayoutTasksTimer.isActive())
        m_postLayoutTasksTimer.stop();

    if (m_didScrollTimer.isActive())
        m_didScrollTimer.stop();

    removeFromAXObjectCache();
    resetScrollbars();

    // Custom scrollbars should already be destroyed at this point
    ASSERT(!horizontalScrollbar() || !horizontalScrollbar()->isCustomScrollbar());
    ASSERT(!verticalScrollbar() || !verticalScrollbar()->isCustomScrollbar());

    setHasHorizontalScrollbar(false); // Remove native scrollbars now before we lose the connection to the HostWindow.
    setHasVerticalScrollbar(false);

    ASSERT(!m_scrollCorner);

    ASSERT(m_frame);
    ASSERT(m_frame->view() != this || !m_frame->contentRenderer());
    // FIXME: Do we need to do something here for OOPI?
    HTMLFrameOwnerElement* ownerElement = m_frame->deprecatedLocalOwner();
    if (ownerElement && ownerElement->ownedWidget() == this)
        ownerElement->setWidget(nullptr);
}

void FrameView::reset()
{
    m_cannotBlitToWindow = false;
    m_isOverlapped = false;
    m_contentIsOpaque = false;
    m_hasPendingLayout = false;
    m_layoutSubtreeRoot = 0;
    m_doFullPaintInvalidation = false;
    m_layoutSchedulingEnabled = true;
    m_inPerformLayout = false;
    m_canInvalidatePaintDuringPerformLayout = false;
    m_inSynchronousPostLayout = false;
    m_layoutCount = 0;
    m_nestedLayoutCount = 0;
    m_postLayoutTasksTimer.stop();
    m_updateWidgetsTimer.stop();
    m_firstLayout = true;
    m_firstLayoutCallbackPending = false;
    m_wasScrolledByUser = false;
    m_safeToPropagateScrollToParent = true;
    m_lastViewportSize = IntSize();
    m_lastZoomFactor = 1.0f;
    m_isTrackingPaintInvalidations = false;
    m_trackedPaintInvalidationRects.clear();
    m_lastPaintTime = 0;
    m_paintBehavior = PaintBehaviorNormal;
    m_isPainting = false;
    m_visuallyNonEmptyCharacterCount = 0;
    m_visuallyNonEmptyPixelCount = 0;
    m_isVisuallyNonEmpty = false;
    m_firstVisuallyNonEmptyLayoutCallbackPending = true;
    m_maintainScrollPositionAnchor = nullptr;
    m_viewportConstrainedObjects.clear();
}

void FrameView::removeFromAXObjectCache()
{
    if (AXObjectCache* cache = axObjectCache())
        cache->remove(this);
}

void FrameView::resetScrollbars()
{
    // Reset the document's scrollbars back to our defaults before we yield the floor.
    m_firstLayout = true;
    setScrollbarsSuppressed(true);
    if (m_canHaveScrollbars)
        setScrollbarModes(ScrollbarAuto, ScrollbarAuto);
    else
        setScrollbarModes(ScrollbarAlwaysOff, ScrollbarAlwaysOff);
    setScrollbarsSuppressed(false);
}

void FrameView::init()
{
    reset();

    m_size = LayoutSize();

    // Propagate the marginwidth/height and scrolling modes to the view.
    // FIXME: Do we need to do this for OOPI?
    Element* ownerElement = m_frame->deprecatedLocalOwner();
    if (ownerElement && (isHTMLFrameElement(*ownerElement) || isHTMLIFrameElement(*ownerElement))) {
        HTMLFrameElementBase* frameElt = toHTMLFrameElementBase(ownerElement);
        if (frameElt->scrollingMode() == ScrollbarAlwaysOff)
            setCanHaveScrollbars(false);
    }
}

void FrameView::prepareForDetach()
{
    RELEASE_ASSERT(!isInPerformLayout());

    if (ScrollAnimator* scrollAnimator = existingScrollAnimator())
        scrollAnimator->cancelAnimations();

    detachCustomScrollbars();
    // When the view is no longer associated with a frame, it needs to be removed from the ax object cache
    // right now, otherwise it won't be able to reach the topDocument()'s axObject cache later.
    removeFromAXObjectCache();

    if (m_frame->page()) {
        if (ScrollingCoordinator* scrollingCoordinator = m_frame->page()->scrollingCoordinator())
            scrollingCoordinator->willDestroyScrollableArea(this);
    }
}

void FrameView::detachCustomScrollbars()
{
    Scrollbar* horizontalBar = horizontalScrollbar();
    if (horizontalBar && horizontalBar->isCustomScrollbar())
        setHasHorizontalScrollbar(false);

    Scrollbar* verticalBar = verticalScrollbar();
    if (verticalBar && verticalBar->isCustomScrollbar())
        setHasVerticalScrollbar(false);

    if (m_scrollCorner) {
        m_scrollCorner->destroy();
        m_scrollCorner = 0;
    }
}

void FrameView::recalculateScrollbarOverlayStyle()
{
    ScrollbarOverlayStyle oldOverlayStyle = scrollbarOverlayStyle();
    ScrollbarOverlayStyle overlayStyle = ScrollbarOverlayStyleDefault;

    Color backgroundColor = documentBackgroundColor();
    // Reduce the background color from RGB to a lightness value
    // and determine which scrollbar style to use based on a lightness
    // heuristic.
    double hue, saturation, lightness;
    backgroundColor.getHSL(hue, saturation, lightness);
    if (lightness <= .5)
        overlayStyle = ScrollbarOverlayStyleLight;

    if (oldOverlayStyle != overlayStyle)
        setScrollbarOverlayStyle(overlayStyle);
}

void FrameView::clear()
{
    reset();
    setScrollbarsSuppressed(true);
}

bool FrameView::didFirstLayout() const
{
    return !m_firstLayout;
}

void FrameView::invalidateRect(const IntRect& rect)
{
    if (!parent()) {
        if (HostWindow* window = hostWindow())
            window->invalidateContentsAndRootView(rect);
        return;
    }

    RenderPart* renderer = m_frame->ownerRenderer();
    if (!renderer)
        return;

    IntRect paintInvalidationRect = rect;
    paintInvalidationRect.move(renderer->borderLeft() + renderer->paddingLeft(),
                     renderer->borderTop() + renderer->paddingTop());
    renderer->invalidatePaintRectangle(paintInvalidationRect);
}

void FrameView::setFrameRect(const IntRect& newRect)
{
    IntRect oldRect = frameRect();
    if (newRect == oldRect)
        return;

    // Autosized font sizes depend on the width of the viewing area.
    bool autosizerNeedsUpdating = false;
    if (newRect.width() != oldRect.width()) {
        if (m_frame->isMainFrame() && m_frame->settings()->textAutosizingEnabled()) {
            autosizerNeedsUpdating = true;
            for (Frame* frame = m_frame.get(); frame; frame = frame->tree().traverseNext()) {
                if (!frame->isLocalFrame())
                    continue;
                if (TextAutosizer* textAutosizer = toLocalFrame(frame)->document()->textAutosizer())
                    textAutosizer->recalculateMultipliers();
            }
        }
    }

    ScrollView::setFrameRect(newRect);

    updateScrollableAreaSet();

    if (autosizerNeedsUpdating) {
        // This needs to be after the call to ScrollView::setFrameRect, because it reads the new width.
        if (FastTextAutosizer* textAutosizer = m_frame->document()->fastTextAutosizer())
            textAutosizer->updatePageInfoInAllFrames();
    }

    if (RenderView* renderView = this->renderView()) {
        if (renderView->usesCompositing())
            renderView->compositor()->frameViewDidChangeSize();
    }

    viewportConstrainedVisibleContentSizeChanged(newRect.width() != oldRect.width(), newRect.height() != oldRect.height());

    if (oldRect.size() != newRect.size()
        && m_frame->isMainFrame()
        && m_frame->settings()->pinchVirtualViewportEnabled())
        page()->frameHost().pinchViewport().mainFrameDidChangeSize();
}

bool FrameView::scheduleAnimation()
{
    if (HostWindow* window = hostWindow()) {
        window->scheduleAnimation();
        return true;
    }
    return false;
}

Page* FrameView::page() const
{
    return frame().page();
}

RenderView* FrameView::renderView() const
{
    return frame().contentRenderer();
}

void FrameView::setCanHaveScrollbars(bool canHaveScrollbars)
{
    m_canHaveScrollbars = canHaveScrollbars;
    ScrollView::setCanHaveScrollbars(canHaveScrollbars);
}

bool FrameView::shouldUseCustomScrollbars(Element*& customScrollbarElement, LocalFrame*& customScrollbarFrame)
{
    customScrollbarElement = 0;
    customScrollbarFrame = 0;

    if (Settings* settings = m_frame->settings()) {
        if (!settings->allowCustomScrollbarInMainFrame() && m_frame->isMainFrame())
            return false;
    }

    // FIXME: We need to update the scrollbar dynamically as documents change (or as doc elements and bodies get discovered that have custom styles).
    Document* doc = m_frame->document();

    // Try the <body> element first as a scrollbar source.
    Element* body = doc ? doc->body() : 0;
    if (body && body->renderer() && body->renderer()->style()->hasPseudoStyle(SCROLLBAR)) {
        customScrollbarElement = body;
        return true;
    }

    // If the <body> didn't have a custom style, then the root element might.
    Element* docElement = doc ? doc->documentElement() : 0;
    if (docElement && docElement->renderer() && docElement->renderer()->style()->hasPseudoStyle(SCROLLBAR)) {
        customScrollbarElement = docElement;
        return true;
    }

    // If we have an owning ipage/LocalFrame element, then it can set the custom scrollbar also.
    RenderPart* frameRenderer = m_frame->ownerRenderer();
    if (frameRenderer && frameRenderer->style()->hasPseudoStyle(SCROLLBAR)) {
        customScrollbarFrame = m_frame.get();
        return true;
    }

    return false;
}

PassRefPtr<Scrollbar> FrameView::createScrollbar(ScrollbarOrientation orientation)
{
    Element* customScrollbarElement = 0;
    LocalFrame* customScrollbarFrame = 0;
    if (shouldUseCustomScrollbars(customScrollbarElement, customScrollbarFrame))
        return RenderScrollbar::createCustomScrollbar(this, orientation, customScrollbarElement, customScrollbarFrame);

    // Nobody set a custom style, so we just use a native scrollbar.
    return ScrollView::createScrollbar(orientation);
}

void FrameView::setContentsSize(const IntSize& size)
{
    if (size == contentsSize())
        return;

    ScrollView::setContentsSize(size);
    ScrollView::contentsResized();

    Page* page = frame().page();
    if (!page)
        return;

    updateScrollableAreaSet();

    page->chrome().contentsSizeChanged(m_frame.get(), size);
}

IntPoint FrameView::clampOffsetAtScale(const IntPoint& offset, float scale) const
{
    IntPoint maxScrollExtent(contentsSize().width() - scrollOrigin().x(), contentsSize().height() - scrollOrigin().y());
    FloatSize scaledSize = unscaledVisibleContentSize();
    if (scale)
        scaledSize.scale(1 / scale);

    IntPoint clampedOffset = offset;
    clampedOffset = clampedOffset.shrunkTo(maxScrollExtent - expandedIntSize(scaledSize));
    clampedOffset = clampedOffset.expandedTo(-scrollOrigin());

    return clampedOffset;
}

void FrameView::adjustViewSize()
{
    RenderView* renderView = this->renderView();
    if (!renderView)
        return;

    ASSERT(m_frame->view() == this);

    const IntRect rect = renderView->documentRect();
    const IntSize& size = rect.size();
    ScrollView::setScrollOrigin(IntPoint(-rect.x(), -rect.y()), !m_frame->document()->printing(), size == contentsSize());

    setContentsSize(size);
}

void FrameView::applyOverflowToViewportAndSetRenderer(RenderObject* o, ScrollbarMode& hMode, ScrollbarMode& vMode)
{
    // Handle the overflow:hidden/scroll case for the body/html elements.  WinIE treats
    // overflow:hidden and overflow:scroll on <body> as applying to the document's
    // scrollbars.  The CSS2.1 draft states that HTML UAs should use the <html> or <body> element and XML/XHTML UAs should
    // use the root element.

    EOverflow overflowX = o->style()->overflowX();
    EOverflow overflowY = o->style()->overflowY();

    if (o->isSVGRoot()) {
        // Don't allow overflow to affect <img> and css backgrounds
        if (toRenderSVGRoot(o)->isEmbeddedThroughSVGImage())
            return;

        // FIXME: evaluate if we can allow overflow for these cases too.
        // Overflow is always hidden when stand-alone SVG documents are embedded.
        if (toRenderSVGRoot(o)->isEmbeddedThroughFrameContainingSVGDocument()) {
            overflowX = OHIDDEN;
            overflowY = OHIDDEN;
        }
    }

    bool ignoreOverflowHidden = false;
    if (m_frame->settings()->ignoreMainFrameOverflowHiddenQuirk() && m_frame->isMainFrame())
        ignoreOverflowHidden = true;

    switch (overflowX) {
        case OHIDDEN:
            if (!ignoreOverflowHidden)
                hMode = ScrollbarAlwaysOff;
            break;
        case OSCROLL:
            hMode = ScrollbarAlwaysOn;
            break;
        case OAUTO:
            hMode = ScrollbarAuto;
            break;
        default:
            // Don't set it at all.
            ;
    }

     switch (overflowY) {
        case OHIDDEN:
            if (!ignoreOverflowHidden)
                vMode = ScrollbarAlwaysOff;
            break;
        case OSCROLL:
            vMode = ScrollbarAlwaysOn;
            break;
        case OAUTO:
            vMode = ScrollbarAuto;
            break;
        default:
            // Don't set it at all.
            ;
    }

    m_viewportRenderer = o;
}

void FrameView::calculateScrollbarModesForLayoutAndSetViewportRenderer(ScrollbarMode& hMode, ScrollbarMode& vMode, ScrollbarModesCalculationStrategy strategy)
{
    m_viewportRenderer = 0;

    // FIXME: How do we handle this for OOPI?
    const HTMLFrameOwnerElement* owner = m_frame->deprecatedLocalOwner();
    if (owner && (owner->scrollingMode() == ScrollbarAlwaysOff)) {
        hMode = ScrollbarAlwaysOff;
        vMode = ScrollbarAlwaysOff;
        return;
    }

    if (m_canHaveScrollbars || strategy == RulesFromWebContentOnly) {
        hMode = ScrollbarAuto;
        vMode = ScrollbarAuto;
    } else {
        hMode = ScrollbarAlwaysOff;
        vMode = ScrollbarAlwaysOff;
    }

    if (!isSubtreeLayout()) {
        Document* document = m_frame->document();
        Node* body = document->body();
        if (isHTMLFrameSetElement(body) && body->renderer()) {
            vMode = ScrollbarAlwaysOff;
            hMode = ScrollbarAlwaysOff;
        } else if (Element* viewportElement = document->viewportDefiningElement()) {
            if (RenderObject* viewportRenderer = viewportElement->renderer()) {
                if (viewportRenderer->style())
                    applyOverflowToViewportAndSetRenderer(viewportRenderer, hMode, vMode);
            }
        }
    }
}

void FrameView::updateAcceleratedCompositingSettings()
{
    if (RenderView* renderView = this->renderView())
        renderView->compositor()->updateAcceleratedCompositingSettings();
}

void FrameView::recalcOverflowAfterStyleChange()
{
    RenderView* renderView = this->renderView();
    ASSERT(renderView);
    if (!renderView->needsOverflowRecalcAfterStyleChange())
        return;

    renderView->recalcOverflowAfterStyleChange();

    if (needsLayout())
        return;

    InUpdateScrollbarsScope inUpdateScrollbarsScope(this);

    bool shouldHaveHorizontalScrollbar = false;
    bool shouldHaveVerticalScrollbar = false;
    computeScrollbarExistence(shouldHaveHorizontalScrollbar, shouldHaveVerticalScrollbar);

    bool hasHorizontalScrollbar = horizontalScrollbar();
    bool hasVerticalScrollbar = verticalScrollbar();
    if (hasHorizontalScrollbar != shouldHaveHorizontalScrollbar
        || hasVerticalScrollbar != shouldHaveVerticalScrollbar) {
        setNeedsLayout();
        return;
    }

    adjustViewSize();
    updateScrollbarGeometry();
}

bool FrameView::usesCompositedScrolling() const
{
    RenderView* renderView = this->renderView();
    if (!renderView)
        return false;
    if (m_frame->settings() && m_frame->settings()->compositedScrollingForFramesEnabled())
        return renderView->compositor()->inCompositingMode();
    return false;
}

GraphicsLayer* FrameView::layerForScrolling() const
{
    RenderView* renderView = this->renderView();
    if (!renderView)
        return 0;
    return renderView->compositor()->scrollLayer();
}

GraphicsLayer* FrameView::layerForHorizontalScrollbar() const
{
    RenderView* renderView = this->renderView();
    if (!renderView)
        return 0;
    return renderView->compositor()->layerForHorizontalScrollbar();
}

GraphicsLayer* FrameView::layerForVerticalScrollbar() const
{
    RenderView* renderView = this->renderView();
    if (!renderView)
        return 0;
    return renderView->compositor()->layerForVerticalScrollbar();
}

GraphicsLayer* FrameView::layerForScrollCorner() const
{
    RenderView* renderView = this->renderView();
    if (!renderView)
        return 0;
    return renderView->compositor()->layerForScrollCorner();
}

bool FrameView::hasCompositedContent() const
{
    // FIXME: change to inCompositingMode. Fails fast/repaint/iframe-scroll-repaint.html.
    if (RenderView* renderView = this->renderView())
        return renderView->compositor()->staleInCompositingMode();
    return false;
}

bool FrameView::isEnclosedInCompositingLayer() const
{
    // FIXME: It's a bug that compositing state isn't always up to date when this is called. crbug.com/366314
    DisableCompositingQueryAsserts disabler;

    RenderObject* frameOwnerRenderer = m_frame->ownerRenderer();
    if (frameOwnerRenderer && frameOwnerRenderer->enclosingLayer()->enclosingCompositingLayerForRepaint())
        return true;

    if (FrameView* parentView = parentFrameView())
        return parentView->isEnclosedInCompositingLayer();

    return false;
}

RenderObject* FrameView::layoutRoot(bool onlyDuringLayout) const
{
    return onlyDuringLayout && layoutPending() ? 0 : m_layoutSubtreeRoot;
}

inline void FrameView::forceLayoutParentViewIfNeeded()
{
    RenderPart* ownerRenderer = m_frame->ownerRenderer();
    if (!ownerRenderer || !ownerRenderer->frame())
        return;

    RenderBox* contentBox = embeddedContentBox();
    if (!contentBox)
        return;

    RenderSVGRoot* svgRoot = toRenderSVGRoot(contentBox);
    if (svgRoot->everHadLayout() && !svgRoot->needsLayout())
        return;

    // If the embedded SVG document appears the first time, the ownerRenderer has already finished
    // layout without knowing about the existence of the embedded SVG document, because RenderReplaced
    // embeddedContentBox() returns 0, as long as the embedded document isn't loaded yet. Before
    // bothering to lay out the SVG document, mark the ownerRenderer needing layout and ask its
    // FrameView for a layout. After that the RenderEmbeddedObject (ownerRenderer) carries the
    // correct size, which RenderSVGRoot::computeReplacedLogicalWidth/Height rely on, when laying
    // out for the first time, or when the RenderSVGRoot size has changed dynamically (eg. via <script>).
    RefPtr<FrameView> frameView = ownerRenderer->frame()->view();

    // Mark the owner renderer as needing layout.
    ownerRenderer->setNeedsLayoutAndPrefWidthsRecalcAndFullPaintInvalidation();

    // Synchronously enter layout, to layout the view containing the host object/embed/iframe.
    ASSERT(frameView);
    frameView->layout();
}

void FrameView::performPreLayoutTasks()
{
    TRACE_EVENT0("webkit", "FrameView::performPreLayoutTasks");
    lifecycle().advanceTo(DocumentLifecycle::InPreLayout);

    // Don't schedule more layouts, we're in one.
    TemporaryChange<bool> changeSchedulingEnabled(m_layoutSchedulingEnabled, false);

    if (!m_nestedLayoutCount && !m_inSynchronousPostLayout && m_postLayoutTasksTimer.isActive()) {
        // This is a new top-level layout. If there are any remaining tasks from the previous layout, finish them now.
        m_inSynchronousPostLayout = true;
        performPostLayoutTasks();
        m_inSynchronousPostLayout = false;
    }

    Document* document = m_frame->document();
    document->notifyResizeForViewportUnits();

    // Viewport-dependent media queries may cause us to need completely different style information.
    if (!document->styleResolver() || document->styleResolver()->mediaQueryAffectedByViewportChange()) {
        document->styleResolverChanged();
        document->mediaQueryAffectingValueChanged();

        // FIXME: This instrumentation event is not strictly accurate since cached media query results
        //        do not persist across StyleResolver rebuilds.
        InspectorInstrumentation::mediaQueryResultChanged(document);
    } else {
        document->evaluateMediaQueryList();
    }

    document->updateRenderTreeIfNeeded();
    lifecycle().advanceTo(DocumentLifecycle::StyleClean);
}

void FrameView::performLayout(RenderObject* rootForThisLayout, bool inSubtreeLayout)
{
    TRACE_EVENT0("webkit", "FrameView::performLayout");

    ScriptForbiddenScope forbidScript;

    ASSERT(!isInPerformLayout());
    lifecycle().advanceTo(DocumentLifecycle::InPerformLayout);

    TemporaryChange<bool> changeInPerformLayout(m_inPerformLayout, true);

    // performLayout is the actual guts of layout().
    // FIXME: The 300 other lines in layout() probably belong in other helper functions
    // so that a single human could understand what layout() is actually doing.

    LayoutState layoutState(*rootForThisLayout);

    forceLayoutParentViewIfNeeded();

    // FIXME (crbug.com/256657): Do not do two layouts for text autosizing.
    rootForThisLayout->layout();
    gatherDebugLayoutRects(rootForThisLayout);

    ResourceLoadPriorityOptimizer::resourceLoadPriorityOptimizer()->updateAllImageResourcePriorities();

    TextAutosizer* textAutosizer = frame().document()->textAutosizer();
    bool autosized;
    {
        AllowPaintInvalidationScope paintInvalidationAllowed(this);
        autosized = textAutosizer && textAutosizer->processSubtree(rootForThisLayout);
    }

    if (autosized && rootForThisLayout->needsLayout()) {
        TRACE_EVENT0("webkit", "2nd layout due to Text Autosizing");
        UseCounter::count(*frame().document(), UseCounter::TextAutosizingLayout);
        rootForThisLayout->layout();
        gatherDebugLayoutRects(rootForThisLayout);
    }

    lifecycle().advanceTo(DocumentLifecycle::AfterPerformLayout);
}

void FrameView::scheduleOrPerformPostLayoutTasks()
{
    if (m_postLayoutTasksTimer.isActive())
        return;

    if (!m_inSynchronousPostLayout) {
        m_inSynchronousPostLayout = true;
        // Calls resumeScheduledEvents()
        performPostLayoutTasks();
        m_inSynchronousPostLayout = false;
    }

    if (!m_postLayoutTasksTimer.isActive() && (needsLayout() || m_inSynchronousPostLayout)) {
        // If we need layout or are already in a synchronous call to postLayoutTasks(),
        // defer widget updates and event dispatch until after we return. postLayoutTasks()
        // can make us need to update again, and we can get stuck in a nasty cycle unless
        // we call it through the timer here.
        m_postLayoutTasksTimer.startOneShot(0, FROM_HERE);
        if (needsLayout())
            layout();
    }
}

void FrameView::layout(bool allowSubtree)
{
    // We should never layout a Document which is not in a LocalFrame.
    ASSERT(m_frame);
    ASSERT(m_frame->view() == this);
    ASSERT(m_frame->page());

    if (isInPerformLayout() || !m_frame->document()->isActive())
        return;

    TRACE_EVENT0("webkit", "FrameView::layout");
    TRACE_EVENT_SCOPED_SAMPLING_STATE("Blink", "Layout");

    // Protect the view from being deleted during layout (in recalcStyle)
    RefPtr<FrameView> protector(this);

    // Every scroll that happens during layout is programmatic.
    TemporaryChange<bool> changeInProgrammaticScroll(m_inProgrammaticScroll, true);

    m_hasPendingLayout = false;
    DocumentLifecycle::Scope lifecycleScope(lifecycle(), DocumentLifecycle::LayoutClean);

    RELEASE_ASSERT(!isPainting());

    TRACE_EVENT_BEGIN1(TRACE_DISABLED_BY_DEFAULT("devtools.timeline"), "Layout", "beginData", InspectorLayoutEvent::beginData(this));
    TRACE_EVENT_INSTANT1(TRACE_DISABLED_BY_DEFAULT("devtools.timeline.stack"), "CallStack", "stack", InspectorCallStackEvent::currentCallStack());
    // FIXME(361045): remove InspectorInstrumentation calls once DevTools Timeline migrates to tracing.
    InspectorInstrumentationCookie cookie = InspectorInstrumentation::willLayout(m_frame.get());

    if (!allowSubtree && isSubtreeLayout()) {
        m_layoutSubtreeRoot->markContainingBlocksForLayout(false);
        m_layoutSubtreeRoot = 0;
    }

    performPreLayoutTasks();

    // If there is only one ref to this view left, then its going to be destroyed as soon as we exit,
    // so there's no point to continuing to layout
    if (protector->hasOneRef())
        return;

    Document* document = m_frame->document();
    bool inSubtreeLayout = isSubtreeLayout();
    RenderObject* rootForThisLayout = inSubtreeLayout ? m_layoutSubtreeRoot : document->renderView();
    if (!rootForThisLayout) {
        // FIXME: Do we need to set m_size here?
        ASSERT_NOT_REACHED();
        return;
    }

    FontCachePurgePreventer fontCachePurgePreventer;
    RenderLayer* layer;
    {
        TemporaryChange<bool> changeSchedulingEnabled(m_layoutSchedulingEnabled, false);

        m_nestedLayoutCount++;
        if (!inSubtreeLayout) {
            Document* document = m_frame->document();
            Node* body = document->body();
            if (body && body->renderer()) {
                if (isHTMLFrameSetElement(*body)) {
                    body->renderer()->setChildNeedsLayout();
                } else if (isHTMLBodyElement(*body)) {
                    if (!m_firstLayout && m_size.height() != layoutSize().height() && body->renderer()->enclosingBox()->stretchesToViewport())
                        body->renderer()->setChildNeedsLayout();
                }
            }
        }
        updateCounters();
        autoSizeIfEnabled();

        ScrollbarMode hMode;
        ScrollbarMode vMode;
        calculateScrollbarModesForLayoutAndSetViewportRenderer(hMode, vMode);

        if (!inSubtreeLayout) {
            // Now set our scrollbar state for the layout.
            ScrollbarMode currentHMode = horizontalScrollbarMode();
            ScrollbarMode currentVMode = verticalScrollbarMode();

            if (m_firstLayout) {
                setScrollbarsSuppressed(true);

                m_doFullPaintInvalidation = true;
                m_firstLayout = false;
                m_firstLayoutCallbackPending = true;
                m_lastViewportSize = layoutSize(IncludeScrollbars);
                m_lastZoomFactor = rootForThisLayout->style()->zoom();

                // Set the initial vMode to AlwaysOn if we're auto.
                if (vMode == ScrollbarAuto)
                    setVerticalScrollbarMode(ScrollbarAlwaysOn); // This causes a vertical scrollbar to appear.
                // Set the initial hMode to AlwaysOff if we're auto.
                if (hMode == ScrollbarAuto)
                    setHorizontalScrollbarMode(ScrollbarAlwaysOff); // This causes a horizontal scrollbar to disappear.

                setScrollbarModes(hMode, vMode);
                setScrollbarsSuppressed(false, true);
            } else if (hMode != currentHMode || vMode != currentVMode) {
                setScrollbarModes(hMode, vMode);
            }

            LayoutSize oldSize = m_size;

            m_size = LayoutSize(layoutSize().width(), layoutSize().height());

            if (oldSize != m_size && !m_firstLayout) {
                RenderBox* rootRenderer = document->documentElement() ? document->documentElement()->renderBox() : 0;
                RenderBox* bodyRenderer = rootRenderer && document->body() ? document->body()->renderBox() : 0;
                if (bodyRenderer && bodyRenderer->stretchesToViewport())
                    bodyRenderer->setChildNeedsLayout();
                else if (rootRenderer && rootRenderer->stretchesToViewport())
                    rootRenderer->setChildNeedsLayout();
            }

            // We need to set m_doFullPaintInvalidation before triggering layout as RenderObject::checkForPaintInvalidation
            // checks the boolean to disable local paint invalidations.
            m_doFullPaintInvalidation |= renderView()->shouldDoFullRepaintForNextLayout();
        }

        layer = rootForThisLayout->enclosingLayer();

        performLayout(rootForThisLayout, inSubtreeLayout);

        m_layoutSubtreeRoot = 0;
    } // Reset m_layoutSchedulingEnabled to its previous value.

    if (!inSubtreeLayout && !toRenderView(rootForThisLayout)->document().printing())
        adjustViewSize();

    layer->updateLayerPositionsAfterLayout(renderView()->layer(), updateLayerPositionFlags(layer, inSubtreeLayout, m_doFullPaintInvalidation));
    renderView()->compositor()->didLayout();

    m_layoutCount++;

    if (AXObjectCache* cache = rootForThisLayout->document().axObjectCache()) {
        const KURL& url = rootForThisLayout->document().url();
        if (url.isValid() && !url.isAboutBlankURL())
            cache->handleLayoutComplete(rootForThisLayout);
    }
    updateAnnotatedRegions();

    ASSERT(!rootForThisLayout->needsLayout());

    if (document->hasListenerType(Document::OVERFLOWCHANGED_LISTENER))
        updateOverflowStatus(layoutSize().width() < contentsWidth(), layoutSize().height() < contentsHeight());

    scheduleOrPerformPostLayoutTasks();

    TRACE_EVENT_END1(TRACE_DISABLED_BY_DEFAULT("devtools.timeline"), "Layout", "endData", InspectorLayoutEvent::endData(rootForThisLayout));
    // FIXME(361045): remove InspectorInstrumentation calls once DevTools Timeline migrates to tracing.
    InspectorInstrumentation::didLayout(cookie, rootForThisLayout);

    m_nestedLayoutCount--;
    if (m_nestedLayoutCount)
        return;

    if (RuntimeEnabledFeatures::repaintAfterLayoutEnabled()) {
        invalidateTree(rootForThisLayout);
    } else if (m_doFullPaintInvalidation) {
        // FIXME: This isn't really right, since the RenderView doesn't fully encompass
        // the visibleContentRect(). It just happens to work out most of the time,
        // since first layouts and printing don't have you scrolled anywhere.
        renderView()->paintInvalidationForWholeRenderer();
    }

    m_doFullPaintInvalidation = false;

#ifndef NDEBUG
    // Post-layout assert that nobody was re-marked as needing layout during layout.
    document->renderView()->assertSubtreeIsLaidOut();
#endif

    // FIXME: It should be not possible to remove the FrameView from the frame/page during layout
    // however m_inPerformLayout is not set for most of this function, so none of our RELEASE_ASSERTS
    // in LocalFrame/Page will fire. One of the post-layout tasks is disconnecting the LocalFrame from
    // the page in fast/frames/crash-remove-iframe-during-object-beforeload-2.html
    // necessitating this check here.
    // ASSERT(frame()->page());
    if (frame().page())
        frame().page()->chrome().client().layoutUpdated(m_frame.get());
}

// The plan is to move to compositor-queried paint invalidation, in which case this
// method would setNeedsRedraw on the GraphicsLayers with invalidations and
// let the compositor pick which to actually draw.
// See http://crbug.com/306706
void FrameView::invalidateTree(RenderObject* root)
{
    ASSERT(RuntimeEnabledFeatures::repaintAfterLayoutEnabled());
    ASSERT(!root->needsLayout());
    // We should only invalidate paints for the outer most layout. This works as
    // we continue to track paint invalidation rects until this function is called.
    ASSERT(!m_nestedLayoutCount);

    TRACE_EVENT1("blink", "FrameView::invalidateTree", "root", root->debugName().ascii());

    // FIXME: really, we're in the paint invalidation phase here, and the compositing queries are legal.
    // Until those states are fully fledged, I'll just disable the ASSERTS.
    DisableCompositingQueryAsserts compositingQueryAssertsDisabler;

    LayoutState rootLayoutState(*root);

    root->invalidateTreeAfterLayout(*root->containerForPaintInvalidation());

    // Invalidate the paint of the frameviews scrollbars if needed
    if (hasVerticalBarDamage())
        invalidateRect(verticalBarDamage());
    if (hasHorizontalBarDamage())
        invalidateRect(horizontalBarDamage());
    resetScrollbarDamage();
}

DocumentLifecycle& FrameView::lifecycle() const
{
    return m_frame->document()->lifecycle();
}

void FrameView::gatherDebugLayoutRects(RenderObject* layoutRoot)
{
    bool isTracing;
    TRACE_EVENT_CATEGORY_GROUP_ENABLED(TRACE_DISABLED_BY_DEFAULT("blink.debug.layout"), &isTracing);
    if (!isTracing)
        return;
    if (!layoutRoot->enclosingLayer()->hasCompositedLayerMapping())
        return;
    GraphicsLayer* graphicsLayer = layoutRoot->enclosingLayer()->compositedLayerMapping()->mainGraphicsLayer();
    if (!graphicsLayer)
        return;

    GraphicsLayerDebugInfo& debugInfo = graphicsLayer->debugInfo();

    debugInfo.currentLayoutRects().clear();
    for (RenderObject* renderer = layoutRoot; renderer; renderer = renderer->nextInPreOrder()) {
        if (renderer->layoutDidGetCalled()) {
            FloatQuad quad = renderer->localToAbsoluteQuad(FloatQuad(renderer->previousPaintInvalidationRect()));
            LayoutRect rect = quad.enclosingBoundingBox();
            debugInfo.currentLayoutRects().append(rect);
            renderer->setLayoutDidGetCalled(false);
        }
    }
}

RenderBox* FrameView::embeddedContentBox() const
{
    RenderView* renderView = this->renderView();
    if (!renderView)
        return 0;

    RenderObject* firstChild = renderView->firstChild();
    if (!firstChild || !firstChild->isBox())
        return 0;

    // Curently only embedded SVG documents participate in the size-negotiation logic.
    if (firstChild->isSVGRoot())
        return toRenderBox(firstChild);

    return 0;
}


void FrameView::addWidget(RenderWidget* object)
{
    m_widgets.add(object);
}

void FrameView::removeWidget(RenderWidget* object)
{
    m_widgets.remove(object);
}

void FrameView::updateWidgetPositions()
{
    Vector<RefPtr<RenderWidget> > widgets;
    copyToVector(m_widgets, widgets);

    // Script or plugins could detach the frame so abort processing if that happens.

    for (size_t i = 0; i < widgets.size() && renderView(); ++i)
        widgets[i]->updateWidgetPosition();

    for (size_t i = 0; i < widgets.size() && renderView(); ++i)
        widgets[i]->widgetPositionsUpdated();
}

void FrameView::addWidgetToUpdate(RenderEmbeddedObject& object)
{
    ASSERT(isInPerformLayout());
    // Tell the DOM element that it needs a widget update.
    Node* node = object.node();
    ASSERT(node);
    if (isHTMLObjectElement(*node) || isHTMLEmbedElement(*node))
        toHTMLPlugInElement(node)->setNeedsWidgetUpdate(true);

    m_widgetUpdateSet.add(&object);
}

void FrameView::setMediaType(const AtomicString& mediaType)
{
    ASSERT(m_frame->document());
    m_frame->document()->mediaQueryAffectingValueChanged();
    m_mediaType = mediaType;
}

AtomicString FrameView::mediaType() const
{
    // See if we have an override type.
    String overrideType;
    InspectorInstrumentation::applyEmulatedMedia(m_frame.get(), &overrideType);
    if (!overrideType.isNull())
        return AtomicString(overrideType);
    return m_mediaType;
}

void FrameView::adjustMediaTypeForPrinting(bool printing)
{
    if (printing) {
        if (m_mediaTypeWhenNotPrinting.isNull())
            m_mediaTypeWhenNotPrinting = mediaType();
            setMediaType("print");
    } else {
        if (!m_mediaTypeWhenNotPrinting.isNull())
            setMediaType(m_mediaTypeWhenNotPrinting);
        m_mediaTypeWhenNotPrinting = nullAtom;
    }
}

bool FrameView::useSlowRepaints(bool considerOverlap) const
{
    // FIXME: It is incorrect to determine blit-scrolling eligibility using dirty compositing state.
    // https://code.google.com/p/chromium/issues/detail?id=357345
    DisableCompositingQueryAsserts disabler;

    if (m_slowRepaintObjectCount > 0)
        return true;

    if (contentsInCompositedLayer())
        return false;

    // The chromium compositor does not support scrolling a non-composited frame within a composited page through
    // the fast scrolling path, so force slow scrolling in that case.
    if (m_frame->owner() && !hasCompositedContent() && m_frame->page() && m_frame->page()->mainFrame()->isLocalFrame() && m_frame->page()->deprecatedLocalMainFrame()->view()->hasCompositedContent())
        return true;

    if (m_isOverlapped && considerOverlap)
        return true;

    if (m_cannotBlitToWindow)
        return true;

    if (!m_contentIsOpaque)
        return true;

    if (FrameView* parentView = parentFrameView())
        return parentView->useSlowRepaints(considerOverlap);

    return false;
}

bool FrameView::useSlowRepaintsIfNotOverlapped() const
{
    return useSlowRepaints(false);
}

bool FrameView::shouldAttemptToScrollUsingFastPath() const
{
    return !useSlowRepaints();
}

bool FrameView::contentsInCompositedLayer() const
{
    RenderView* renderView = this->renderView();
    if (renderView && renderView->compositingState() == PaintsIntoOwnBacking) {
        GraphicsLayer* layer = renderView->layer()->compositedLayerMapping()->mainGraphicsLayer();
        if (layer && layer->drawsContent())
            return true;
    }

    return false;
}

void FrameView::setCannotBlitToWindow()
{
    m_cannotBlitToWindow = true;
}

void FrameView::addSlowRepaintObject()
{
    if (!m_slowRepaintObjectCount++) {
        if (Page* page = m_frame->page()) {
            if (ScrollingCoordinator* scrollingCoordinator = page->scrollingCoordinator())
                scrollingCoordinator->frameViewHasSlowRepaintObjectsDidChange(this);
        }
    }
}

void FrameView::removeSlowRepaintObject()
{
    ASSERT(m_slowRepaintObjectCount > 0);
    m_slowRepaintObjectCount--;
    if (!m_slowRepaintObjectCount) {
        if (Page* page = m_frame->page()) {
            if (ScrollingCoordinator* scrollingCoordinator = page->scrollingCoordinator())
                scrollingCoordinator->frameViewHasSlowRepaintObjectsDidChange(this);
        }
    }
}

void FrameView::addViewportConstrainedObject(RenderObject* object)
{
    if (!m_viewportConstrainedObjects)
        m_viewportConstrainedObjects = adoptPtr(new ViewportConstrainedObjectSet);

    if (!m_viewportConstrainedObjects->contains(object)) {
        m_viewportConstrainedObjects->add(object);

        if (Page* page = m_frame->page()) {
            if (ScrollingCoordinator* scrollingCoordinator = page->scrollingCoordinator())
                scrollingCoordinator->frameViewFixedObjectsDidChange(this);
        }
    }
}

void FrameView::removeViewportConstrainedObject(RenderObject* object)
{
    if (m_viewportConstrainedObjects && m_viewportConstrainedObjects->contains(object)) {
        m_viewportConstrainedObjects->remove(object);

        if (Page* page = m_frame->page()) {
            if (ScrollingCoordinator* scrollingCoordinator = page->scrollingCoordinator())
                scrollingCoordinator->frameViewFixedObjectsDidChange(this);
        }
    }
}

LayoutRect FrameView::viewportConstrainedVisibleContentRect() const
{
    LayoutRect viewportRect = visibleContentRect();
    // Ignore overhang. No-op when not using rubber banding.
    viewportRect.setLocation(clampScrollPosition(scrollPosition()));
    return viewportRect;
}

void FrameView::viewportConstrainedVisibleContentSizeChanged(bool widthChanged, bool heightChanged)
{
    if (!hasViewportConstrainedObjects())
        return;

    // If viewport is not enabled, frameRect change will cause layout size change and then layout.
    // Otherwise, viewport constrained objects need their layout flags set separately to ensure
    // they are positioned correctly. In the virtual-viewport pinch mode frame rect changes wont
    // necessarily cause a layout size change so only take this early-out if we're in old-style
    // pinch.
    if (m_frame->settings()
        && !m_frame->settings()->viewportEnabled()
        && !m_frame->settings()->pinchVirtualViewportEnabled())
        return;

    ViewportConstrainedObjectSet::const_iterator end = m_viewportConstrainedObjects->end();
    for (ViewportConstrainedObjectSet::const_iterator it = m_viewportConstrainedObjects->begin(); it != end; ++it) {
        RenderObject* renderer = *it;
        RenderStyle* style = renderer->style();
        if (widthChanged) {
            if (style->width().isFixed() && (style->left().isAuto() || style->right().isAuto()))
                renderer->setNeedsPositionedMovementLayout();
            else
                renderer->setNeedsLayoutAndFullPaintInvalidation();
        }
        if (heightChanged) {
            if (style->height().isFixed() && (style->top().isAuto() || style->bottom().isAuto()))
                renderer->setNeedsPositionedMovementLayout();
            else
                renderer->setNeedsLayoutAndFullPaintInvalidation();
        }
    }
}

IntSize FrameView::scrollOffsetForFixedPosition() const
{
    return toIntSize(clampScrollPosition(scrollPosition()));
}

IntPoint FrameView::lastKnownMousePosition() const
{
    return m_frame->eventHandler().lastKnownMousePosition();
}

bool FrameView::shouldSetCursor() const
{
    Page* page = frame().page();
    return page && page->visibilityState() != PageVisibilityStateHidden && page->focusController().isActive() && page->settings().deviceSupportsMouse();
}

void FrameView::scrollContentsIfNeededRecursive()
{
    scrollContentsIfNeeded();

    for (Frame* child = m_frame->tree().firstChild(); child; child = child->tree().nextSibling()) {
        if (!child->isLocalFrame())
            continue;
        if (FrameView* view = toLocalFrame(child)->view())
            view->scrollContentsIfNeededRecursive();
    }
}

void FrameView::scrollContentsIfNeeded()
{
    bool didScroll = !pendingScrollDelta().isZero();
    ScrollView::scrollContentsIfNeeded();
    if (didScroll)
        updateFixedElementPaintInvalidationRectsAfterScroll();
}

bool FrameView::scrollContentsFastPath(const IntSize& scrollDelta, const IntRect& rectToScroll, const IntRect& clipRect)
{
    if (!m_viewportConstrainedObjects || m_viewportConstrainedObjects->isEmpty()) {
        hostWindow()->scroll(scrollDelta, rectToScroll, clipRect);
        return true;
    }

    const bool isCompositedContentLayer = contentsInCompositedLayer();

    // Get the rects of the fixed objects visible in the rectToScroll
    Region regionToUpdate;
    ViewportConstrainedObjectSet::const_iterator end = m_viewportConstrainedObjects->end();
    for (ViewportConstrainedObjectSet::const_iterator it = m_viewportConstrainedObjects->begin(); it != end; ++it) {
        RenderObject* renderer = *it;
        // m_viewportConstrainedObjects should not contain non-viewport constrained objects.
        ASSERT(renderer->style()->hasViewportConstrainedPosition());

        // Fixed items should always have layers.
        ASSERT(renderer->hasLayer());
        RenderLayer* layer = toRenderBoxModelObject(renderer)->layer();

        // Layers that paint into their ancestor or into a grouped backing will still need
        // to apply a paint invalidation. If the layer paints into its own backing, then
        // it does not need paint invalidation just to scroll.
        if (layer->compositingState() == PaintsIntoOwnBacking)
            continue;

        if (layer->viewportConstrainedNotCompositedReason() == RenderLayer::NotCompositedForBoundsOutOfView
            || layer->viewportConstrainedNotCompositedReason() == RenderLayer::NotCompositedForNoVisibleContent) {
            // Don't invalidate for invisible fixed layers.
            continue;
        }

        if (layer->hasAncestorWithFilterOutsets()) {
            // If the fixed layer has a blur/drop-shadow filter applied on at least one of its parents, we cannot
            // scroll using the fast path, otherwise the outsets of the filter will be moved around the page.
            return false;
        }

        IntRect updateRect = pixelSnappedIntRect(layer->repainter().repaintRectIncludingNonCompositingDescendants());

        const RenderLayerModelObject* repaintContainer = layer->renderer()->containerForPaintInvalidation();
        if (repaintContainer && !repaintContainer->isRenderView()) {
            // If the fixed-position layer is contained by a composited layer that is not its containing block,
            // then we have to invalidate that enclosing layer, not the RenderView.
            // FIXME: Why do we need to issue this invalidation? Won't the fixed position element just scroll
            //        with the enclosing layer.
            updateRect.moveBy(scrollPosition());
            IntRect previousRect = updateRect;
            previousRect.move(scrollDelta);
            updateRect.unite(previousRect);
            layer->renderer()->invalidatePaintUsingContainer(repaintContainer, updateRect, InvalidationScroll);
        } else {
            // Coalesce the paint invalidations that will be issued to the renderView.
            updateRect = contentsToRootView(updateRect);
            if (!isCompositedContentLayer && clipsPaintInvalidations())
                updateRect.intersect(rectToScroll);
            if (!updateRect.isEmpty())
                regionToUpdate.unite(updateRect);
        }
    }

    // 1) scroll
    hostWindow()->scroll(scrollDelta, rectToScroll, clipRect);

    // 2) update the area of fixed objects that has been invalidated
    Vector<IntRect> subRectsToUpdate = regionToUpdate.rects();
    size_t viewportConstrainedObjectsCount = subRectsToUpdate.size();
    for (size_t i = 0; i < viewportConstrainedObjectsCount; ++i) {
        IntRect updateRect = subRectsToUpdate[i];
        IntRect scrolledRect = updateRect;
        scrolledRect.move(-scrollDelta);
        updateRect.unite(scrolledRect);
        if (isCompositedContentLayer) {
            updateRect = rootViewToContents(updateRect);
            ASSERT(renderView());
            renderView()->layer()->repainter().setBackingNeedsRepaintInRect(updateRect);
            continue;
        }
        if (clipsPaintInvalidations())
            updateRect.intersect(rectToScroll);
        hostWindow()->invalidateContentsAndRootView(updateRect);
    }

    return true;
}

void FrameView::scrollContentsSlowPath(const IntRect& updateRect)
{
    if (contentsInCompositedLayer()) {
        IntRect updateRect = visibleContentRect();
        ASSERT(renderView());
        renderView()->layer()->repainter().setBackingNeedsRepaintInRect(updateRect);
    }
    if (RenderPart* frameRenderer = m_frame->ownerRenderer()) {
        if (isEnclosedInCompositingLayer()) {
            LayoutRect rect(frameRenderer->borderLeft() + frameRenderer->paddingLeft(),
                            frameRenderer->borderTop() + frameRenderer->paddingTop(),
                            visibleWidth(), visibleHeight());
            frameRenderer->invalidatePaintRectangle(rect);
            return;
        }
    }

    ScrollView::scrollContentsSlowPath(updateRect);
}

// Note that this gets called at painting time.
void FrameView::setIsOverlapped(bool isOverlapped)
{
    m_isOverlapped = isOverlapped;
}

void FrameView::setContentIsOpaque(bool contentIsOpaque)
{
    m_contentIsOpaque = contentIsOpaque;
}

void FrameView::restoreScrollbar()
{
    setScrollbarsSuppressed(false);
}

bool FrameView::scrollToFragment(const KURL& url)
{
    // If our URL has no ref, then we have no place we need to jump to.
    // OTOH If CSS target was set previously, we want to set it to 0, recalc
    // and possibly paint invalidation because :target pseudo class may have been
    // set (see bug 11321).
    if (!url.hasFragmentIdentifier() && !m_frame->document()->cssTarget())
        return false;

    String fragmentIdentifier = url.fragmentIdentifier();
    if (scrollToAnchor(fragmentIdentifier))
        return true;

    // Try again after decoding the ref, based on the document's encoding.
    if (m_frame->document()->encoding().isValid())
        return scrollToAnchor(decodeURLEscapeSequences(fragmentIdentifier, m_frame->document()->encoding()));

    return false;
}

bool FrameView::scrollToAnchor(const String& name)
{
    ASSERT(m_frame->document());

    if (!m_frame->document()->isRenderingReady()) {
        m_frame->document()->setGotoAnchorNeededAfterStylesheetsLoad(true);
        return false;
    }

    m_frame->document()->setGotoAnchorNeededAfterStylesheetsLoad(false);

    Element* anchorNode = m_frame->document()->findAnchor(name);

    // Setting to null will clear the current target.
    m_frame->document()->setCSSTarget(anchorNode);

    if (m_frame->document()->isSVGDocument()) {
        if (SVGSVGElement* svg = SVGDocumentExtensions::rootElement(*m_frame->document())) {
            svg->setupInitialView(name, anchorNode);
            if (!anchorNode)
                return true;
        }
    }

    // Implement the rule that "" and "top" both mean top of page as in other browsers.
    if (!anchorNode && !(name.isEmpty() || equalIgnoringCase(name, "top")))
        return false;

    maintainScrollPositionAtAnchor(anchorNode ? static_cast<Node*>(anchorNode) : m_frame->document());

    // If the anchor accepts keyboard focus, move focus there to aid users relying on keyboard navigation.
    if (anchorNode && anchorNode->isFocusable())
        m_frame->document()->setFocusedElement(anchorNode);

    return true;
}

void FrameView::maintainScrollPositionAtAnchor(Node* anchorNode)
{
    m_maintainScrollPositionAnchor = anchorNode;
    if (!m_maintainScrollPositionAnchor)
        return;

    // We need to update the layout before scrolling, otherwise we could
    // really mess things up if an anchor scroll comes at a bad moment.
    m_frame->document()->updateRenderTreeIfNeeded();
    // Only do a layout if changes have occurred that make it necessary.
    RenderView* renderView = this->renderView();
    if (renderView && renderView->needsLayout())
        layout();
    else
        scrollToAnchor();
}

void FrameView::scrollElementToRect(Element* element, const IntRect& rect)
{
    // FIXME(http://crbug.com/371896) - This method shouldn't be manually doing
    // coordinate transformations to the PinchViewport.
    IntRect targetRect(rect);

    m_frame->document()->updateLayoutIgnorePendingStylesheets();

    bool pinchVirtualViewportEnabled = m_frame->settings()->pinchVirtualViewportEnabled();

    if (pinchVirtualViewportEnabled) {
        PinchViewport& pinchViewport = m_frame->page()->frameHost().pinchViewport();

        IntSize pinchViewportSize = expandedIntSize(pinchViewport.visibleRect().size());
        targetRect.moveBy(ceiledIntPoint(pinchViewport.visibleRect().location()));
        targetRect.setSize(pinchViewportSize.shrunkTo(targetRect.size()));
    }

    LayoutRect bounds = element->boundingBox();
    int centeringOffsetX = (targetRect.width() - bounds.width()) / 2;
    int centeringOffsetY = (targetRect.height() - bounds.height()) / 2;

    IntPoint targetOffset(
        bounds.x() - centeringOffsetX - targetRect.x(),
        bounds.y() - centeringOffsetY - targetRect.y());

    setScrollPosition(targetOffset);

    if (pinchVirtualViewportEnabled) {
        IntPoint remainder = IntPoint(targetOffset - scrollPosition());
        m_frame->page()->frameHost().pinchViewport().move(remainder);
    }
}

void FrameView::setScrollPosition(const IntPoint& scrollPoint)
{
    TemporaryChange<bool> changeInProgrammaticScroll(m_inProgrammaticScroll, true);
    m_maintainScrollPositionAnchor = nullptr;

    IntPoint newScrollPosition = adjustScrollPositionWithinRange(scrollPoint);

    if (newScrollPosition == scrollPosition())
        return;

    ScrollView::setScrollPosition(newScrollPosition);
}

void FrameView::setScrollPositionNonProgrammatically(const IntPoint& scrollPoint)
{
    IntPoint newScrollPosition = adjustScrollPositionWithinRange(scrollPoint);

    if (newScrollPosition == scrollPosition())
        return;

    TemporaryChange<bool> changeInProgrammaticScroll(m_inProgrammaticScroll, false);
    notifyScrollPositionChanged(newScrollPosition);
}

IntSize FrameView::layoutSize(IncludeScrollbarsInRect scrollbarInclusion) const
{
    return scrollbarInclusion == ExcludeScrollbars ? excludeScrollbars(m_layoutSize) : m_layoutSize;
}

void FrameView::setLayoutSize(const IntSize& size)
{
    ASSERT(!layoutSizeFixedToFrameSize());

    setLayoutSizeInternal(size);
}

void FrameView::scrollPositionChanged()
{
    setWasScrolledByUser(true);

    Document* document = m_frame->document();
    document->enqueueScrollEventForNode(document);

    m_frame->eventHandler().dispatchFakeMouseMoveEventSoon();

    if (RenderView* renderView = document->renderView()) {
        if (renderView->usesCompositing())
            renderView->compositor()->frameViewDidScroll();
    }

    if (m_didScrollTimer.isActive())
        m_didScrollTimer.stop();
    m_didScrollTimer.startOneShot(resourcePriorityUpdateDelayAfterScroll, FROM_HERE);

    if (AXObjectCache* cache = m_frame->document()->existingAXObjectCache())
        cache->handleScrollPositionChanged(this);

    frame().loader().saveScrollState();
}

void FrameView::didScrollTimerFired(Timer<FrameView>*)
{
    if (m_frame->document() && m_frame->document()->renderView()) {
        ResourceLoadPriorityOptimizer::resourceLoadPriorityOptimizer()->updateAllImageResourcePriorities();
    }
}

void FrameView::updateLayersAndCompositingAfterScrollIfNeeded()
{
    // Nothing to do after scrolling if there are no fixed position elements.
    if (!hasViewportConstrainedObjects())
        return;

    RefPtr<FrameView> protect(this);

    // If there fixed position elements, scrolling may cause compositing layers to change.
    // Update widget and layer positions after scrolling, but only if we're not inside of
    // layout.
    if (!m_nestedLayoutCount) {
        updateWidgetPositions();
        if (RenderView* renderView = this->renderView()) {
            renderView->layer()->updateLayerPositionsAfterDocumentScroll();
            renderView->layer()->setNeedsCompositingInputsUpdate();
            renderView->compositor()->setNeedsCompositingUpdate(CompositingUpdateAfterCompositingInputChange);
        }
    }
}

void FrameView::updateFixedElementPaintInvalidationRectsAfterScroll()
{
    if (!hasViewportConstrainedObjects())
        return;

    // Update the paint invalidation rects for fixed elements after scrolling and invalidation to reflect
    // the new scroll position.
    ViewportConstrainedObjectSet::const_iterator end = m_viewportConstrainedObjects->end();
    for (ViewportConstrainedObjectSet::const_iterator it = m_viewportConstrainedObjects->begin(); it != end; ++it) {
        RenderObject* renderer = *it;
        // m_viewportConstrainedObjects should not contain non-viewport constrained objects.
        ASSERT(renderer->style()->hasViewportConstrainedPosition());

        // Fixed items should always have layers.
        ASSERT(renderer->hasLayer());

        RenderLayer* layer = toRenderBoxModelObject(renderer)->layer();

        // Don't need to do this for composited fixed items.
        if (layer->compositingState() == PaintsIntoOwnBacking)
            continue;

        // Also don't need to do this for invisible items.
        if (layer->viewportConstrainedNotCompositedReason() == RenderLayer::NotCompositedForBoundsOutOfView
            || layer->viewportConstrainedNotCompositedReason() == RenderLayer::NotCompositedForNoVisibleContent)
            continue;

        layer->repainter().computeRepaintRectsIncludingNonCompositingDescendants();
    }
}

bool FrameView::isRubberBandInProgress() const
{
    if (scrollbarsSuppressed())
        return false;

    // If the main thread updates the scroll position for this FrameView, we should return
    // ScrollAnimator::isRubberBandInProgress().
    if (ScrollAnimator* scrollAnimator = existingScrollAnimator())
        return scrollAnimator->isRubberBandInProgress();

    return false;
}

HostWindow* FrameView::hostWindow() const
{
    Page* page = frame().page();
    if (!page)
        return 0;
    return &page->chrome();
}

void FrameView::contentRectangleForPaintInvalidation(const IntRect& r)
{
    ASSERT(paintInvalidationIsAllowed());
    ASSERT(!m_frame->owner());

    if (m_isTrackingPaintInvalidations) {
        IntRect paintInvalidationRect = r;
        paintInvalidationRect.move(-scrollOffset());
        m_trackedPaintInvalidationRects.append(paintInvalidationRect);
        // FIXME: http://crbug.com/368518. Eventually, invalidateContentRectangleForPaint
        // is going away entirely once all layout tests are FCM. In the short
        // term, no code should be tracking non-composited FrameView paint invalidations.
        RELEASE_ASSERT_NOT_REACHED();
    }

    ScrollView::contentRectangleForPaintInvalidation(r);
}

void FrameView::contentsResized()
{
    if (m_frame->isMainFrame() && m_frame->document()) {
        if (FastTextAutosizer* textAutosizer = m_frame->document()->fastTextAutosizer())
            textAutosizer->updatePageInfoInAllFrames();
    }

    ScrollView::contentsResized();
    setNeedsLayout();
}

void FrameView::scrollbarExistenceDidChange()
{
    // We check to make sure the view is attached to a frame() as this method can
    // be triggered before the view is attached by LocalFrame::createView(...) setting
    // various values such as setScrollBarModes(...) for example.  An ASSERT is
    // triggered when a view is layout before being attached to a frame().
    if (!frame().view())
        return;

    // Note that simply having overlay scrollbars is not sufficient to be
    // certain that scrollbars' presence does not impact layout. This should
    // also check if custom scrollbars (as reported by shouldUseCustomScrollbars)
    // are in use as well.
    // http://crbug.com/269692
    bool useOverlayScrollbars = ScrollbarTheme::theme()->usesOverlayScrollbars();

    if (!useOverlayScrollbars && needsLayout())
        layout();

    if (renderView() && renderView()->usesCompositing()) {
        renderView()->compositor()->frameViewScrollbarsExistenceDidChange();

        if (!useOverlayScrollbars)
            renderView()->compositor()->frameViewDidChangeSize();
    }
}

void FrameView::handleLoadCompleted()
{
    // Once loading has completed, allow autoSize one last opportunity to
    // reduce the size of the frame.
    autoSizeIfEnabled();
}

void FrameView::scheduleRelayout()
{
    ASSERT(m_frame->view() == this);

    if (isSubtreeLayout()) {
        m_layoutSubtreeRoot->markContainingBlocksForLayout(false);
        m_layoutSubtreeRoot = 0;
    }
    if (!m_layoutSchedulingEnabled)
        return;
    if (!needsLayout())
        return;
    if (!m_frame->document()->shouldScheduleLayout())
        return;
    TRACE_EVENT_INSTANT1(TRACE_DISABLED_BY_DEFAULT("devtools.timeline"), "InvalidateLayout", "frame", m_frame.get());
    TRACE_EVENT_INSTANT1(TRACE_DISABLED_BY_DEFAULT("devtools.timeline.stack"), "CallStack", "stack", InspectorCallStackEvent::currentCallStack());
    // FIXME(361045): remove InspectorInstrumentation calls once DevTools Timeline migrates to tracing.
    InspectorInstrumentation::didInvalidateLayout(m_frame.get());

    if (m_hasPendingLayout)
        return;
    m_hasPendingLayout = true;

    page()->animator().scheduleVisualUpdate();
    lifecycle().ensureStateAtMost(DocumentLifecycle::StyleClean);
}

static bool isObjectAncestorContainerOf(RenderObject* ancestor, RenderObject* descendant)
{
    for (RenderObject* r = descendant; r; r = r->container()) {
        if (r == ancestor)
            return true;
    }
    return false;
}

void FrameView::scheduleRelayoutOfSubtree(RenderObject* relayoutRoot)
{
    ASSERT(m_frame->view() == this);

    // FIXME: Should this call shouldScheduleLayout instead?
    if (!m_frame->document()->isActive())
        return;

    RenderView* renderView = this->renderView();
    if (renderView && renderView->needsLayout()) {
        if (relayoutRoot)
            relayoutRoot->markContainingBlocksForLayout(false);
        return;
    }

    if (layoutPending() || !m_layoutSchedulingEnabled) {
        if (m_layoutSubtreeRoot != relayoutRoot) {
            if (isObjectAncestorContainerOf(m_layoutSubtreeRoot, relayoutRoot)) {
                // Keep the current root
                relayoutRoot->markContainingBlocksForLayout(false, m_layoutSubtreeRoot);
                ASSERT(!m_layoutSubtreeRoot->container() || !m_layoutSubtreeRoot->container()->needsLayout());
            } else if (isSubtreeLayout() && isObjectAncestorContainerOf(relayoutRoot, m_layoutSubtreeRoot)) {
                // Re-root at relayoutRoot
                m_layoutSubtreeRoot->markContainingBlocksForLayout(false, relayoutRoot);
                m_layoutSubtreeRoot = relayoutRoot;
                ASSERT(!m_layoutSubtreeRoot->container() || !m_layoutSubtreeRoot->container()->needsLayout());
            } else {
                // Just do a full relayout
                if (isSubtreeLayout())
                    m_layoutSubtreeRoot->markContainingBlocksForLayout(false);
                m_layoutSubtreeRoot = 0;
                relayoutRoot->markContainingBlocksForLayout(false);
            }
        }
    } else if (m_layoutSchedulingEnabled) {
        m_layoutSubtreeRoot = relayoutRoot;
        ASSERT(!m_layoutSubtreeRoot->container() || !m_layoutSubtreeRoot->container()->needsLayout());
        m_hasPendingLayout = true;

        page()->animator().scheduleVisualUpdate();
        lifecycle().ensureStateAtMost(DocumentLifecycle::StyleClean);
    }
    TRACE_EVENT_INSTANT1(TRACE_DISABLED_BY_DEFAULT("devtools.timeline"), "InvalidateLayout", "frame", m_frame.get());
    TRACE_EVENT_INSTANT1(TRACE_DISABLED_BY_DEFAULT("devtools.timeline.stack"), "CallStack", "stack", InspectorCallStackEvent::currentCallStack());
    // FIXME(361045): remove InspectorInstrumentation calls once DevTools Timeline migrates to tracing.
    InspectorInstrumentation::didInvalidateLayout(m_frame.get());
}

bool FrameView::layoutPending() const
{
    // FIXME: This should check Document::lifecycle instead.
    return m_hasPendingLayout;
}

bool FrameView::isInPerformLayout() const
{
    ASSERT(m_inPerformLayout == (lifecycle().state() == DocumentLifecycle::InPerformLayout));
    return m_inPerformLayout;
}

bool FrameView::needsLayout() const
{
    // This can return true in cases where the document does not have a body yet.
    // Document::shouldScheduleLayout takes care of preventing us from scheduling
    // layout in that case.

    RenderView* renderView = this->renderView();
    return layoutPending()
        || (renderView && renderView->needsLayout())
        || isSubtreeLayout();
}

void FrameView::setNeedsLayout()
{
    if (RenderView* renderView = this->renderView())
        renderView->setNeedsLayout();
}

bool FrameView::isTransparent() const
{
    return m_isTransparent;
}

void FrameView::setTransparent(bool isTransparent)
{
    m_isTransparent = isTransparent;
    DisableCompositingQueryAsserts disabler;
    if (renderView() && renderView()->layer()->hasCompositedLayerMapping())
        renderView()->layer()->compositedLayerMapping()->updateContentsOpaque();
}

bool FrameView::hasOpaqueBackground() const
{
    return !m_isTransparent && !m_baseBackgroundColor.hasAlpha();
}

Color FrameView::baseBackgroundColor() const
{
    return m_baseBackgroundColor;
}

void FrameView::setBaseBackgroundColor(const Color& backgroundColor)
{
    m_baseBackgroundColor = backgroundColor;

    if (renderView() && renderView()->layer()->hasCompositedLayerMapping()) {
        CompositedLayerMappingPtr compositedLayerMapping = renderView()->layer()->compositedLayerMapping();
        compositedLayerMapping->updateContentsOpaque();
        if (compositedLayerMapping->mainGraphicsLayer())
            compositedLayerMapping->mainGraphicsLayer()->setNeedsDisplay();
    }
    recalculateScrollbarOverlayStyle();
}

void FrameView::updateBackgroundRecursively(const Color& backgroundColor, bool transparent)
{
    for (Frame* frame = m_frame.get(); frame; frame = frame->tree().traverseNext(m_frame.get())) {
        if (!frame->isLocalFrame())
            continue;
        if (FrameView* view = toLocalFrame(frame)->view()) {
            view->setTransparent(transparent);
            view->setBaseBackgroundColor(backgroundColor);
        }
    }
}

void FrameView::scrollToAnchor()
{
    RefPtrWillBeRawPtr<Node> anchorNode = m_maintainScrollPositionAnchor;
    if (!anchorNode)
        return;

    if (!anchorNode->renderer())
        return;

    LayoutRect rect;
    if (anchorNode != m_frame->document())
        rect = anchorNode->boundingBox();

    // Scroll nested layers and frames to reveal the anchor.
    // Align to the top and to the closest side (this matches other browsers).
    anchorNode->renderer()->scrollRectToVisible(rect, ScrollAlignment::alignToEdgeIfNeeded, ScrollAlignment::alignTopAlways);

    if (AXObjectCache* cache = m_frame->document()->existingAXObjectCache())
        cache->handleScrolledToAnchor(anchorNode.get());

    // scrollRectToVisible can call into setScrollPosition(), which resets m_maintainScrollPositionAnchor.
    m_maintainScrollPositionAnchor = anchorNode;
}

bool FrameView::updateWidgets()
{
    // This is always called from updateWidgetsTimerFired.
    // m_updateWidgetsTimer should only be scheduled if we have widgets to update.
    // Thus I believe we can stop checking isEmpty here, and just ASSERT isEmpty:
    ASSERT(!m_widgetUpdateSet.isEmpty());
    if (m_nestedLayoutCount > 1 || m_widgetUpdateSet.isEmpty())
        return true;

    // Need to swap because script will run inside the below loop and invalidate the iterator.
    EmbeddedObjectSet objects;
    objects.swap(m_widgetUpdateSet);

    for (EmbeddedObjectSet::iterator it = objects.begin(); it != objects.end(); ++it) {
        RenderEmbeddedObject& object = **it;
        HTMLPlugInElement* element = toHTMLPlugInElement(object.node());

        // The object may have already been destroyed (thus node cleared),
        // but FrameView holds a manual ref, so it won't have been deleted.
        if (!element)
            continue;

        // No need to update if it's already crashed or known to be missing.
        if (object.showsUnavailablePluginIndicator())
            continue;

        if (element->needsWidgetUpdate())
            element->updateWidget();
        object.updateWidgetPosition();

        // Prevent plugins from causing infinite updates of themselves.
        // FIXME: Do we really need to prevent this?
        m_widgetUpdateSet.remove(&object);
    }

    return m_widgetUpdateSet.isEmpty();
}

void FrameView::updateWidgetsTimerFired(Timer<FrameView>*)
{
    ASSERT(!isInPerformLayout());
    RefPtr<FrameView> protect(this);
    m_updateWidgetsTimer.stop();
    for (unsigned i = 0; i < maxUpdateWidgetsIterations; ++i) {
        if (updateWidgets())
            return;
    }
}

void FrameView::flushAnyPendingPostLayoutTasks()
{
    ASSERT(!isInPerformLayout());
    if (m_postLayoutTasksTimer.isActive())
        performPostLayoutTasks();
    if (m_updateWidgetsTimer.isActive())
        updateWidgetsTimerFired(0);
}

void FrameView::scheduleUpdateWidgetsIfNecessary()
{
    ASSERT(!isInPerformLayout());
    if (m_updateWidgetsTimer.isActive() || m_widgetUpdateSet.isEmpty())
        return;
    m_updateWidgetsTimer.startOneShot(0, FROM_HERE);
}

void FrameView::performPostLayoutTasks()
{
    // FIXME: We can reach here, even when the page is not active!
    // http/tests/inspector/elements/html-link-import.html and many other
    // tests hit that case.
    // We should ASSERT(isActive()); or at least return early if we can!
    ASSERT(!isInPerformLayout()); // Always before or after performLayout(), part of the highest-level layout() call.
    TRACE_EVENT0("webkit", "FrameView::performPostLayoutTasks");
    RefPtr<FrameView> protect(this);

    m_postLayoutTasksTimer.stop();

    m_frame->selection().setCaretRectNeedsUpdate();

    {
        // Hits in compositing/overflow/do-not-repaint-if-scrolling-composited-layers.html
        DisableCompositingQueryAsserts disabler;
        m_frame->selection().updateAppearance();
    }

    ASSERT(m_frame->document());
    if (m_nestedLayoutCount <= 1) {
        if (m_firstLayoutCallbackPending)
            m_firstLayoutCallbackPending = false;

        // Ensure that we always send this eventually.
        if (!m_frame->document()->parsing() && m_frame->loader().stateMachine()->committedFirstRealDocumentLoad())
            m_isVisuallyNonEmpty = true;

        // If the layout was done with pending sheets, we are not in fact visually non-empty yet.
        if (m_isVisuallyNonEmpty && !m_frame->document()->didLayoutWithPendingStylesheets() && m_firstVisuallyNonEmptyLayoutCallbackPending) {
            m_firstVisuallyNonEmptyLayoutCallbackPending = false;
            // FIXME: This callback is probably not needed, but is currently used
            // by android for setting the background color.
            m_frame->loader().client()->dispatchDidFirstVisuallyNonEmptyLayout();
        }
    }

    FontFaceSet::didLayout(*m_frame->document());

    updateWidgetPositions();

    // Plugins could have torn down the page inside updateWidgetPositions().
    if (!renderView())
        return;

    scheduleUpdateWidgetsIfNecessary();

    if (Page* page = m_frame->page()) {
        if (ScrollingCoordinator* scrollingCoordinator = page->scrollingCoordinator())
            scrollingCoordinator->notifyLayoutUpdated();
    }

    scrollToAnchor();

    sendResizeEventIfNeeded();
}

void FrameView::sendResizeEventIfNeeded()
{
    ASSERT(m_frame);

    RenderView* renderView = this->renderView();
    if (!renderView || renderView->document().printing())
        return;

    IntSize currentSize = layoutSize(IncludeScrollbars);
    float currentZoomFactor = renderView->style()->zoom();

    bool shouldSendResizeEvent = currentSize != m_lastViewportSize || currentZoomFactor != m_lastZoomFactor;

    m_lastViewportSize = currentSize;
    m_lastZoomFactor = currentZoomFactor;

    if (!shouldSendResizeEvent)
        return;

    m_frame->document()->enqueueResizeEvent();

    if (m_frame->isMainFrame())
        InspectorInstrumentation::didResizeMainFrame(m_frame->page());
}

void FrameView::postLayoutTimerFired(Timer<FrameView>*)
{
    performPostLayoutTasks();
}

void FrameView::updateCounters()
{
    RenderView* view = renderView();
    if (!view->hasRenderCounters())
        return;

    for (RenderObject* renderer = view; renderer; renderer = renderer->nextInPreOrder()) {
        if (!renderer->isCounter())
            continue;

        toRenderCounter(renderer)->updateCounter();
    }
}

void FrameView::autoSizeIfEnabled()
{
    if (!m_shouldAutoSize)
        return;

    if (m_inAutoSize)
        return;

    TemporaryChange<bool> changeInAutoSize(m_inAutoSize, true);

    Document* document = frame().document();
    if (!document || !document->isActive())
        return;

    Element* documentElement = document->documentElement();
    if (!documentElement)
        return;

    // If this is the first time we run autosize, start from small height and
    // allow it to grow.
    if (!m_didRunAutosize)
        resize(frameRect().width(), m_minAutoSize.height());

    IntSize size = frameRect().size();

    // Do the resizing twice. The first time is basically a rough calculation using the preferred width
    // which may result in a height change during the second iteration.
    for (int i = 0; i < 2; i++) {
        // Update various sizes including contentsSize, scrollHeight, etc.
        document->updateLayoutIgnorePendingStylesheets();

        RenderView* renderView = document->renderView();
        if (!renderView)
            return;

        int width = renderView->minPreferredLogicalWidth();

        RenderBox* documentRenderBox = documentElement->renderBox();
        if (!documentRenderBox)
            return;

        int height = documentRenderBox->scrollHeight();
        IntSize newSize(width, height);

        // Check to see if a scrollbar is needed for a given dimension and
        // if so, increase the other dimension to account for the scrollbar.
        // Since the dimensions are only for the view rectangle, once a
        // dimension exceeds the maximum, there is no need to increase it further.
        if (newSize.width() > m_maxAutoSize.width()) {
            RefPtr<Scrollbar> localHorizontalScrollbar = horizontalScrollbar();
            if (!localHorizontalScrollbar)
                localHorizontalScrollbar = createScrollbar(HorizontalScrollbar);
            if (!localHorizontalScrollbar->isOverlayScrollbar())
                newSize.setHeight(newSize.height() + localHorizontalScrollbar->height());

            // Don't bother checking for a vertical scrollbar because the width is at
            // already greater the maximum.
        } else if (newSize.height() > m_maxAutoSize.height()) {
            RefPtr<Scrollbar> localVerticalScrollbar = verticalScrollbar();
            if (!localVerticalScrollbar)
                localVerticalScrollbar = createScrollbar(VerticalScrollbar);
            if (!localVerticalScrollbar->isOverlayScrollbar())
                newSize.setWidth(newSize.width() + localVerticalScrollbar->width());

            // Don't bother checking for a horizontal scrollbar because the height is
            // already greater the maximum.
        }

        // Ensure the size is at least the min bounds.
        newSize = newSize.expandedTo(m_minAutoSize);

        // Bound the dimensions by the max bounds and determine what scrollbars to show.
        ScrollbarMode horizonalScrollbarMode = ScrollbarAlwaysOff;
        if (newSize.width() > m_maxAutoSize.width()) {
            newSize.setWidth(m_maxAutoSize.width());
            horizonalScrollbarMode = ScrollbarAlwaysOn;
        }
        ScrollbarMode verticalScrollbarMode = ScrollbarAlwaysOff;
        if (newSize.height() > m_maxAutoSize.height()) {
            newSize.setHeight(m_maxAutoSize.height());
            verticalScrollbarMode = ScrollbarAlwaysOn;
        }

        if (newSize == size)
            continue;

        // While loading only allow the size to increase (to avoid twitching during intermediate smaller states)
        // unless autoresize has just been turned on or the maximum size is smaller than the current size.
        if (m_didRunAutosize && size.height() <= m_maxAutoSize.height() && size.width() <= m_maxAutoSize.width()
            && !m_frame->document()->loadEventFinished() && (newSize.height() < size.height() || newSize.width() < size.width()))
            break;

        resize(newSize.width(), newSize.height());
        // Force the scrollbar state to avoid the scrollbar code adding them and causing them to be needed. For example,
        // a vertical scrollbar may cause text to wrap and thus increase the height (which is the only reason the scollbar is needed).
        setVerticalScrollbarLock(false);
        setHorizontalScrollbarLock(false);
        setScrollbarModes(horizonalScrollbarMode, verticalScrollbarMode, true, true);
    }
    m_didRunAutosize = true;
}

void FrameView::updateOverflowStatus(bool horizontalOverflow, bool verticalOverflow)
{
    if (!m_viewportRenderer)
        return;

    if (m_overflowStatusDirty) {
        m_horizontalOverflow = horizontalOverflow;
        m_verticalOverflow = verticalOverflow;
        m_overflowStatusDirty = false;
        return;
    }

    bool horizontalOverflowChanged = (m_horizontalOverflow != horizontalOverflow);
    bool verticalOverflowChanged = (m_verticalOverflow != verticalOverflow);

    if (horizontalOverflowChanged || verticalOverflowChanged) {
        m_horizontalOverflow = horizontalOverflow;
        m_verticalOverflow = verticalOverflow;

        RefPtrWillBeRawPtr<OverflowEvent> event = OverflowEvent::create(horizontalOverflowChanged, horizontalOverflow, verticalOverflowChanged, verticalOverflow);
        event->setTarget(m_viewportRenderer->node());
        m_frame->document()->enqueueAnimationFrameEvent(event.release());
    }

}

IntRect FrameView::windowClipRect(IncludeScrollbarsInRect scrollbarInclusion) const
{
    ASSERT(m_frame->view() == this);

    if (paintsEntireContents())
        return IntRect(IntPoint(), contentsSize());

    // Set our clip rect to be our contents.
    IntRect clipRect = contentsToWindow(visibleContentRect(scrollbarInclusion));
    if (!m_frame->deprecatedLocalOwner())
        return clipRect;

    // Take our owner element and get its clip rect.
    // FIXME: Do we need to do this for remote frames?
    HTMLFrameOwnerElement* ownerElement = m_frame->deprecatedLocalOwner();
    FrameView* parentView = ownerElement->document().view();
    if (parentView)
        clipRect.intersect(parentView->windowClipRectForFrameOwner(ownerElement));
    return clipRect;
}

IntRect FrameView::windowClipRectForFrameOwner(const HTMLFrameOwnerElement* ownerElement) const
{
    // The renderer can sometimes be null when style="display:none" interacts
    // with external content and plugins.
    if (!ownerElement->renderer())
        return windowClipRect();

    // If we have no layer, just return our window clip rect.
    const RenderLayer* enclosingLayer = ownerElement->renderer()->enclosingLayer();
    if (!enclosingLayer)
        return windowClipRect();

    // FIXME: childrenClipRect relies on compositingState, which is not necessarily up to date.
    // https://code.google.com/p/chromium/issues/detail?id=343769
    DisableCompositingQueryAsserts disabler;

    // Apply the clip from the layer.
    IntRect clipRect = contentsToWindow(pixelSnappedIntRect(enclosingLayer->clipper().childrenClipRect()));
    return intersection(clipRect, windowClipRect());
}

bool FrameView::isActive() const
{
    Page* page = frame().page();
    return page && page->focusController().isActive();
}

void FrameView::scrollTo(const IntSize& newOffset)
{
    LayoutSize offset = scrollOffset();
    ScrollView::scrollTo(newOffset);
    if (offset != scrollOffset()) {
        updateLayersAndCompositingAfterScrollIfNeeded();
        scrollPositionChanged();
    }
    frame().loader().client()->didChangeScrollOffset();
}

void FrameView::invalidateScrollbarRect(Scrollbar* scrollbar, const IntRect& rect)
{
    // Add in our offset within the FrameView.
    IntRect dirtyRect = rect;
    dirtyRect.moveBy(scrollbar->location());

    if (RuntimeEnabledFeatures::repaintAfterLayoutEnabled() && isInPerformLayout()) {
        if (scrollbar == verticalScrollbar()) {
            m_verticalBarDamage = dirtyRect;
            m_hasVerticalBarDamage = true;
        } else {
            m_horizontalBarDamage = dirtyRect;
            m_hasHorizontalBarDamage = true;
        }
    } else {
        invalidateRect(dirtyRect);
    }
}

void FrameView::getTickmarks(Vector<IntRect>& tickmarks) const
{
    if (!m_tickmarks.isEmpty())
        tickmarks = m_tickmarks;
    else
        tickmarks = frame().document()->markers().renderedRectsForMarkers(DocumentMarker::TextMatch);
}

IntRect FrameView::windowResizerRect() const
{
    Page* page = frame().page();
    if (!page)
        return IntRect();
    return page->chrome().windowResizerRect();
}

void FrameView::setVisibleContentScaleFactor(float visibleContentScaleFactor)
{
    if (m_visibleContentScaleFactor == visibleContentScaleFactor)
        return;

    m_visibleContentScaleFactor = visibleContentScaleFactor;
    updateScrollbars(scrollOffset());
}

void FrameView::setInputEventsTransformForEmulation(const IntSize& offset, float contentScaleFactor)
{
    m_inputEventsOffsetForEmulation = offset;
    m_inputEventsScaleFactorForEmulation = contentScaleFactor;
}

IntSize FrameView::inputEventsOffsetForEmulation() const
{
    return m_inputEventsOffsetForEmulation;
}

float FrameView::inputEventsScaleFactor() const
{
    float pageScale = m_frame->settings()->pinchVirtualViewportEnabled()
        ? m_frame->page()->frameHost().pinchViewport().scale()
        : visibleContentScaleFactor();
    return pageScale * m_inputEventsScaleFactorForEmulation;
}

bool FrameView::scrollbarsCanBeActive() const
{
    if (m_frame->view() != this)
        return false;

    return !!m_frame->document();
}

IntRect FrameView::scrollableAreaBoundingBox() const
{
    RenderPart* ownerRenderer = frame().ownerRenderer();
    if (!ownerRenderer)
        return frameRect();

    return ownerRenderer->absoluteContentQuad().enclosingBoundingBox();
}

bool FrameView::isScrollable()
{
    // Check for:
    // 1) If there an actual overflow.
    // 2) display:none or visibility:hidden set to self or inherited.
    // 3) overflow{-x,-y}: hidden;
    // 4) scrolling: no;

    // Covers #1
    IntSize contentsSize = this->contentsSize();
    IntSize visibleContentSize = visibleContentRect().size();
    if ((contentsSize.height() <= visibleContentSize.height() && contentsSize.width() <= visibleContentSize.width()))
        return false;

    // Covers #2.
    // FIXME: Do we need to fix this for OOPI?
    HTMLFrameOwnerElement* owner = m_frame->deprecatedLocalOwner();
    if (owner && (!owner->renderer() || !owner->renderer()->visibleToHitTesting()))
        return false;

    // Cover #3 and #4.
    ScrollbarMode horizontalMode;
    ScrollbarMode verticalMode;
    calculateScrollbarModesForLayoutAndSetViewportRenderer(horizontalMode, verticalMode, RulesFromWebContentOnly);
    if (horizontalMode == ScrollbarAlwaysOff && verticalMode == ScrollbarAlwaysOff)
        return false;

    return true;
}

void FrameView::updateScrollableAreaSet()
{
    // That ensures that only inner frames are cached.
    FrameView* parentFrameView = this->parentFrameView();
    if (!parentFrameView)
        return;

    if (!isScrollable()) {
        parentFrameView->removeScrollableArea(this);
        return;
    }

    parentFrameView->addScrollableArea(this);
}

bool FrameView::shouldSuspendScrollAnimations() const
{
    return m_frame->loader().state() != FrameStateComplete;
}

void FrameView::scrollbarStyleChanged()
{
    // FIXME: Why does this only apply to the main frame?
    if (!m_frame->isMainFrame())
        return;
    ScrollView::scrollbarStyleChanged();
}

void FrameView::notifyPageThatContentAreaWillPaint() const
{
    Page* page = m_frame->page();
    if (!page)
        return;

    contentAreaWillPaint();

    if (!m_scrollableAreas)
        return;

    for (HashSet<ScrollableArea*>::const_iterator it = m_scrollableAreas->begin(), end = m_scrollableAreas->end(); it != end; ++it) {
        ScrollableArea* scrollableArea = *it;

        if (!scrollableArea->scrollbarsCanBeActive())
            continue;

        scrollableArea->contentAreaWillPaint();
    }
}

bool FrameView::scrollAnimatorEnabled() const
{
    return m_frame->settings() && m_frame->settings()->scrollAnimatorEnabled();
}

void FrameView::updateAnnotatedRegions()
{
    Document* document = m_frame->document();
    if (!document->hasAnnotatedRegions())
        return;
    Vector<AnnotatedRegionValue> newRegions;
    document->renderBox()->collectAnnotatedRegions(newRegions);
    if (newRegions == document->annotatedRegions())
        return;
    document->setAnnotatedRegions(newRegions);
    if (Page* page = m_frame->page())
        page->chrome().client().annotatedRegionsChanged();
}

void FrameView::updateScrollCorner()
{
    RefPtr<RenderStyle> cornerStyle;
    IntRect cornerRect = scrollCornerRect();
    Document* doc = m_frame->document();

    if (doc && !cornerRect.isEmpty()) {
        // Try the <body> element first as a scroll corner source.
        if (Element* body = doc->body()) {
            if (RenderObject* renderer = body->renderer())
                cornerStyle = renderer->getUncachedPseudoStyle(PseudoStyleRequest(SCROLLBAR_CORNER), renderer->style());
        }

        if (!cornerStyle) {
            // If the <body> didn't have a custom style, then the root element might.
            if (Element* docElement = doc->documentElement()) {
                if (RenderObject* renderer = docElement->renderer())
                    cornerStyle = renderer->getUncachedPseudoStyle(PseudoStyleRequest(SCROLLBAR_CORNER), renderer->style());
            }
        }

        if (!cornerStyle) {
            // If we have an owning ipage/LocalFrame element, then it can set the custom scrollbar also.
            if (RenderPart* renderer = m_frame->ownerRenderer())
                cornerStyle = renderer->getUncachedPseudoStyle(PseudoStyleRequest(SCROLLBAR_CORNER), renderer->style());
        }
    }

    if (cornerStyle) {
        if (!m_scrollCorner)
            m_scrollCorner = RenderScrollbarPart::createAnonymous(doc);
        m_scrollCorner->setStyle(cornerStyle.release());
        invalidateScrollCorner(cornerRect);
    } else if (m_scrollCorner) {
        m_scrollCorner->destroy();
        m_scrollCorner = 0;
    }

    ScrollView::updateScrollCorner();
}

void FrameView::paintScrollCorner(GraphicsContext* context, const IntRect& cornerRect)
{
    if (context->updatingControlTints()) {
        updateScrollCorner();
        return;
    }

    if (m_scrollCorner) {
        bool needsBackgorund = m_frame->isMainFrame();
        if (needsBackgorund)
            context->fillRect(cornerRect, baseBackgroundColor());
        m_scrollCorner->paintIntoRect(context, cornerRect.location(), cornerRect);
        return;
    }

    ScrollView::paintScrollCorner(context, cornerRect);
}

void FrameView::paintScrollbar(GraphicsContext* context, Scrollbar* bar, const IntRect& rect)
{
    bool needsBackgorund = bar->isCustomScrollbar() && m_frame->isMainFrame();
    if (needsBackgorund) {
        IntRect toFill = bar->frameRect();
        toFill.intersect(rect);
        context->fillRect(toFill, baseBackgroundColor());
    }

    ScrollView::paintScrollbar(context, bar, rect);
}

Color FrameView::documentBackgroundColor() const
{
    // <https://bugs.webkit.org/show_bug.cgi?id=59540> We blend the background color of
    // the document and the body against the base background color of the frame view.
    // Background images are unfortunately impractical to include.

    Color result = baseBackgroundColor();
    if (!frame().document())
        return result;

    Element* htmlElement = frame().document()->documentElement();
    Element* bodyElement = frame().document()->body();

    // We take the aggregate of the base background color
    // the <html> background color, and the <body>
    // background color to find the document color. The
    // addition of the base background color is not
    // technically part of the document background, but it
    // otherwise poses problems when the aggregate is not
    // fully opaque.
    if (htmlElement && htmlElement->renderer())
        result = result.blend(htmlElement->renderer()->style()->visitedDependentColor(CSSPropertyBackgroundColor));
    if (bodyElement && bodyElement->renderer())
        result = result.blend(bodyElement->renderer()->style()->visitedDependentColor(CSSPropertyBackgroundColor));

    return result;
}

bool FrameView::hasCustomScrollbars() const
{
    const HashSet<RefPtr<Widget> >* viewChildren = children();
    HashSet<RefPtr<Widget> >::const_iterator end = viewChildren->end();
    for (HashSet<RefPtr<Widget> >::const_iterator current = viewChildren->begin(); current != end; ++current) {
        Widget* widget = current->get();
        if (widget->isFrameView()) {
            if (toFrameView(widget)->hasCustomScrollbars())
                return true;
        } else if (widget->isScrollbar()) {
            Scrollbar* scrollbar = static_cast<Scrollbar*>(widget);
            if (scrollbar->isCustomScrollbar())
                return true;
        }
    }

    return false;
}

FrameView* FrameView::parentFrameView() const
{
    if (!parent())
        return 0;

    Frame* parentFrame = m_frame->tree().parent();
    if (parentFrame && parentFrame->isLocalFrame())
        return toLocalFrame(parentFrame)->view();

    return 0;
}

void FrameView::updateControlTints()
{
    // This is called when control tints are changed from aqua/graphite to clear and vice versa.
    // We do a "fake" paint, and when the theme gets a paint call, it can then do an invalidate.
    // This is only done if the theme supports control tinting. It's up to the theme and platform
    // to define when controls get the tint and to call this function when that changes.

    // Optimize the common case where we bring a window to the front while it's still empty.
    if (m_frame->document()->url().isEmpty())
        return;

    // FIXME: We shouldn't rely on the paint code to implement :window-inactive on custom scrollbars.
    if (!RenderTheme::theme().supportsControlTints() && !hasCustomScrollbars())
        return;

    // Updating layout can run script, which can tear down the FrameView.
    RefPtr<FrameView> protector(this);
    updateLayoutAndStyleForPainting();

    // FIXME: The use of paint seems like overkill: crbug.com/236892
    GraphicsContext context(0); // NULL canvas to get a non-painting context.
    context.setUpdatingControlTints(true);
    paint(&context, frameRect());
}

bool FrameView::wasScrolledByUser() const
{
    return m_wasScrolledByUser;
}

void FrameView::setWasScrolledByUser(bool wasScrolledByUser)
{
    if (m_inProgrammaticScroll)
        return;
    m_maintainScrollPositionAnchor = nullptr;
    m_wasScrolledByUser = wasScrolledByUser;
}

void FrameView::paintContents(GraphicsContext* p, const IntRect& rect)
{
    Document* document = m_frame->document();

#ifndef NDEBUG
    bool fillWithRed;
    if (document->printing())
        fillWithRed = false; // Printing, don't fill with red (can't remember why).
    else if (m_frame->owner())
        fillWithRed = false; // Subframe, don't fill with red.
    else if (isTransparent())
        fillWithRed = false; // Transparent, don't fill with red.
    else if (m_paintBehavior & PaintBehaviorSelectionOnly)
        fillWithRed = false; // Selections are transparent, don't fill with red.
    else if (m_nodeToDraw)
        fillWithRed = false; // Element images are transparent, don't fill with red.
    else
        fillWithRed = true;

    if (fillWithRed)
        p->fillRect(rect, Color(0xFF, 0, 0));
#endif

    RenderView* renderView = this->renderView();
    if (!renderView) {
        WTF_LOG_ERROR("called FrameView::paint with nil renderer");
        return;
    }

    ASSERT(!needsLayout());
    if (needsLayout())
        return;

    TRACE_EVENT1(TRACE_DISABLED_BY_DEFAULT("devtools.timeline"), "Paint", "data", InspectorPaintEvent::data(renderView, rect, 0));
    TRACE_EVENT_INSTANT1(TRACE_DISABLED_BY_DEFAULT("devtools.timeline.stack"), "CallStack", "stack", InspectorCallStackEvent::currentCallStack());
    // FIXME(361045): remove InspectorInstrumentation calls once DevTools Timeline migrates to tracing.
    InspectorInstrumentation::willPaint(renderView, 0);

    bool isTopLevelPainter = !s_inPaintContents;
    s_inPaintContents = true;

    FontCachePurgePreventer fontCachePurgePreventer;

    PaintBehavior oldPaintBehavior = m_paintBehavior;

    if (FrameView* parentView = parentFrameView()) {
        if (parentView->paintBehavior() & PaintBehaviorFlattenCompositingLayers)
            m_paintBehavior |= PaintBehaviorFlattenCompositingLayers;
    }

    if (m_paintBehavior == PaintBehaviorNormal)
        document->markers().invalidateRenderedRectsForMarkersInRect(rect);

    if (document->printing())
        m_paintBehavior |= PaintBehaviorFlattenCompositingLayers;

    ASSERT(!m_isPainting);
    m_isPainting = true;

    // m_nodeToDraw is used to draw only one element (and its descendants)
    RenderObject* renderer = m_nodeToDraw ? m_nodeToDraw->renderer() : 0;
    RenderLayer* rootLayer = renderView->layer();

#ifndef NDEBUG
    renderView->assertSubtreeIsLaidOut();
    RenderObject::SetLayoutNeededForbiddenScope forbidSetNeedsLayout(*rootLayer->renderer());
#endif

    rootLayer->paint(p, rect, m_paintBehavior, renderer);

    if (rootLayer->containsDirtyOverlayScrollbars())
        rootLayer->paintOverlayScrollbars(p, rect, m_paintBehavior, renderer);

    m_isPainting = false;

    m_paintBehavior = oldPaintBehavior;
    m_lastPaintTime = currentTime();

    // Regions may have changed as a result of the visibility/z-index of element changing.
    if (document->annotatedRegionsDirty())
        updateAnnotatedRegions();

    if (isTopLevelPainter) {
        // Everythin that happens after paintContents completions is considered
        // to be part of the next frame.
        s_currentFrameTimeStamp = currentTime();
        s_inPaintContents = false;
    }

    InspectorInstrumentation::didPaint(renderView, 0, p, rect);
}

void FrameView::setPaintBehavior(PaintBehavior behavior)
{
    m_paintBehavior = behavior;
}

PaintBehavior FrameView::paintBehavior() const
{
    return m_paintBehavior;
}

bool FrameView::isPainting() const
{
    return m_isPainting;
}

void FrameView::setNodeToDraw(Node* node)
{
    m_nodeToDraw = node;
}

void FrameView::paintOverhangAreas(GraphicsContext* context, const IntRect& horizontalOverhangArea, const IntRect& verticalOverhangArea, const IntRect& dirtyRect)
{
    if (context->paintingDisabled())
        return;

    if (m_frame->document()->printing())
        return;

    if (m_frame->isMainFrame()) {
        if (m_frame->page()->chrome().client().paintCustomOverhangArea(context, horizontalOverhangArea, verticalOverhangArea, dirtyRect))
            return;
    }

    ScrollView::paintOverhangAreas(context, horizontalOverhangArea, verticalOverhangArea, dirtyRect);
}

void FrameView::updateLayoutAndStyleForPainting()
{
    // Updating layout can run script, which can tear down the FrameView.
    RefPtr<FrameView> protector(this);

    updateLayoutAndStyleIfNeededRecursive();

    if (RenderView* view = renderView()) {
        InspectorInstrumentation::willUpdateLayerTree(view->frame());

        view->compositor()->updateIfNeededRecursive();

        if (view->compositor()->inCompositingMode() && m_frame->isMainFrame())
            m_frame->page()->scrollingCoordinator()->updateAfterCompositingChangeIfNeeded();

        InspectorInstrumentation::didUpdateLayerTree(view->frame());
    }

    scrollContentsIfNeededRecursive();
}

void FrameView::updateLayoutAndStyleIfNeededRecursive()
{
    // We have to crawl our entire tree looking for any FrameViews that need
    // layout and make sure they are up to date.
    // Mac actually tests for intersection with the dirty region and tries not to
    // update layout for frames that are outside the dirty region.  Not only does this seem
    // pointless (since those frames will have set a zero timer to layout anyway), but
    // it is also incorrect, since if two frames overlap, the first could be excluded from the dirty
    // region but then become included later by the second frame adding rects to the dirty region
    // when it lays out.

    m_frame->document()->updateRenderTreeIfNeeded();

    if (needsLayout())
        layout();

    // FIXME: Calling layout() shouldn't trigger scripe execution or have any
    // observable effects on the frame tree but we're not quite there yet.
    Vector<RefPtr<FrameView> > frameViews;
    for (Frame* child = m_frame->tree().firstChild(); child; child = child->tree().nextSibling()) {
        if (!child->isLocalFrame())
            continue;
        if (FrameView* view = toLocalFrame(child)->view())
            frameViews.append(view);
    }

    const Vector<RefPtr<FrameView> >::iterator end = frameViews.end();
    for (Vector<RefPtr<FrameView> >::iterator it = frameViews.begin(); it != end; ++it)
        (*it)->updateLayoutAndStyleIfNeededRecursive();

    // When an <iframe> gets composited, it triggers an extra style recalc in its containing FrameView.
    // To avoid pushing an invalid tree for display, we have to check for this case and do another
    // style recalc. The extra style recalc needs to happen after our child <iframes> were updated.
    // FIXME: We shouldn't be triggering an extra style recalc in the first place.
    if (m_frame->document()->hasSVGFilterElementsRequiringLayerUpdate()) {
        m_frame->document()->updateRenderTreeIfNeeded();

        if (needsLayout())
            layout();
    }

    // These asserts ensure that parent frames are clean, when child frames finished updating layout and style.
    ASSERT(!needsLayout());
    ASSERT(!m_frame->document()->hasSVGFilterElementsRequiringLayerUpdate());
#ifndef NDEBUG
    m_frame->document()->renderView()->assertRendererLaidOut();
#endif

}

void FrameView::enableAutoSizeMode(bool enable, const IntSize& minSize, const IntSize& maxSize)
{
    ASSERT(!enable || !minSize.isEmpty());
    ASSERT(minSize.width() <= maxSize.width());
    ASSERT(minSize.height() <= maxSize.height());

    if (m_shouldAutoSize == enable && m_minAutoSize == minSize && m_maxAutoSize == maxSize)
        return;


    m_shouldAutoSize = enable;
    m_minAutoSize = minSize;
    m_maxAutoSize = maxSize;
    m_didRunAutosize = false;

    setLayoutSizeFixedToFrameSize(enable);
    setNeedsLayout();
    scheduleRelayout();
    if (m_shouldAutoSize)
        return;

    // Since autosize mode forces the scrollbar mode, change them to being auto.
    setVerticalScrollbarLock(false);
    setHorizontalScrollbarLock(false);
    setScrollbarModes(ScrollbarAuto, ScrollbarAuto);
}

void FrameView::forceLayout(bool allowSubtree)
{
    layout(allowSubtree);
}

void FrameView::forceLayoutForPagination(const FloatSize& pageSize, const FloatSize& originalPageSize, float maximumShrinkFactor)
{
    // Dumping externalRepresentation(m_frame->renderer()).ascii() is a good trick to see
    // the state of things before and after the layout
    if (RenderView* renderView = this->renderView()) {
        float pageLogicalWidth = renderView->style()->isHorizontalWritingMode() ? pageSize.width() : pageSize.height();
        float pageLogicalHeight = renderView->style()->isHorizontalWritingMode() ? pageSize.height() : pageSize.width();

        LayoutUnit flooredPageLogicalWidth = static_cast<LayoutUnit>(pageLogicalWidth);
        LayoutUnit flooredPageLogicalHeight = static_cast<LayoutUnit>(pageLogicalHeight);
        renderView->setLogicalWidth(flooredPageLogicalWidth);
        renderView->setPageLogicalHeight(flooredPageLogicalHeight);
        renderView->setNeedsLayoutAndPrefWidthsRecalcAndFullPaintInvalidation();
        forceLayout();

        // If we don't fit in the given page width, we'll lay out again. If we don't fit in the
        // page width when shrunk, we will lay out at maximum shrink and clip extra content.
        // FIXME: We are assuming a shrink-to-fit printing implementation.  A cropping
        // implementation should not do this!
        bool horizontalWritingMode = renderView->style()->isHorizontalWritingMode();
        const LayoutRect& documentRect = renderView->documentRect();
        LayoutUnit docLogicalWidth = horizontalWritingMode ? documentRect.width() : documentRect.height();
        if (docLogicalWidth > pageLogicalWidth) {
            FloatSize expectedPageSize(std::min<float>(documentRect.width().toFloat(), pageSize.width() * maximumShrinkFactor), std::min<float>(documentRect.height().toFloat(), pageSize.height() * maximumShrinkFactor));
            FloatSize maxPageSize = m_frame->resizePageRectsKeepingRatio(FloatSize(originalPageSize.width(), originalPageSize.height()), expectedPageSize);
            pageLogicalWidth = horizontalWritingMode ? maxPageSize.width() : maxPageSize.height();
            pageLogicalHeight = horizontalWritingMode ? maxPageSize.height() : maxPageSize.width();

            flooredPageLogicalWidth = static_cast<LayoutUnit>(pageLogicalWidth);
            flooredPageLogicalHeight = static_cast<LayoutUnit>(pageLogicalHeight);
            renderView->setLogicalWidth(flooredPageLogicalWidth);
            renderView->setPageLogicalHeight(flooredPageLogicalHeight);
            renderView->setNeedsLayoutAndPrefWidthsRecalcAndFullPaintInvalidation();
            forceLayout();

            const LayoutRect& updatedDocumentRect = renderView->documentRect();
            LayoutUnit docLogicalHeight = horizontalWritingMode ? updatedDocumentRect.height() : updatedDocumentRect.width();
            LayoutUnit docLogicalTop = horizontalWritingMode ? updatedDocumentRect.y() : updatedDocumentRect.x();
            LayoutUnit docLogicalRight = horizontalWritingMode ? updatedDocumentRect.maxX() : updatedDocumentRect.maxY();
            LayoutUnit clippedLogicalLeft = 0;
            if (!renderView->style()->isLeftToRightDirection())
                clippedLogicalLeft = docLogicalRight - pageLogicalWidth;
            LayoutRect overflow(clippedLogicalLeft, docLogicalTop, pageLogicalWidth, docLogicalHeight);

            if (!horizontalWritingMode)
                overflow = overflow.transposedRect();
            renderView->clearLayoutOverflow();
            renderView->addLayoutOverflow(overflow); // This is how we clip in case we overflow again.
        }
    }

    adjustViewSize();
}

IntRect FrameView::convertFromRenderer(const RenderObject& renderer, const IntRect& rendererRect) const
{
    IntRect rect = pixelSnappedIntRect(enclosingLayoutRect(renderer.localToAbsoluteQuad(FloatRect(rendererRect)).boundingBox()));

    // Convert from page ("absolute") to FrameView coordinates.
    rect.moveBy(-scrollPosition());

    return rect;
}

IntRect FrameView::convertToRenderer(const RenderObject& renderer, const IntRect& viewRect) const
{
    IntRect rect = viewRect;

    // Convert from FrameView coords into page ("absolute") coordinates.
    rect.moveBy(scrollPosition());

    // FIXME: we don't have a way to map an absolute rect down to a local quad, so just
    // move the rect for now.
    rect.setLocation(roundedIntPoint(renderer.absoluteToLocal(rect.location(), UseTransforms)));
    return rect;
}

IntPoint FrameView::convertFromRenderer(const RenderObject& renderer, const IntPoint& rendererPoint) const
{
    IntPoint point = roundedIntPoint(renderer.localToAbsolute(rendererPoint, UseTransforms));

    // Convert from page ("absolute") to FrameView coordinates.
    point.moveBy(-scrollPosition());
    return point;
}

IntPoint FrameView::convertToRenderer(const RenderObject& renderer, const IntPoint& viewPoint) const
{
    IntPoint point = viewPoint;

    // Convert from FrameView coords into page ("absolute") coordinates.
    point += IntSize(scrollX(), scrollY());

    return roundedIntPoint(renderer.absoluteToLocal(point, UseTransforms));
}

IntRect FrameView::convertToContainingView(const IntRect& localRect) const
{
    if (const ScrollView* parentScrollView = toScrollView(parent())) {
        if (parentScrollView->isFrameView()) {
            const FrameView* parentView = toFrameView(parentScrollView);
            // Get our renderer in the parent view
            RenderPart* renderer = m_frame->ownerRenderer();
            if (!renderer)
                return localRect;

            IntRect rect(localRect);
            // Add borders and padding??
            rect.move(renderer->borderLeft() + renderer->paddingLeft(),
                renderer->borderTop() + renderer->paddingTop());
            return parentView->convertFromRenderer(*renderer, rect);
        }

        return Widget::convertToContainingView(localRect);
    }

    return localRect;
}

IntRect FrameView::convertFromContainingView(const IntRect& parentRect) const
{
    if (const ScrollView* parentScrollView = toScrollView(parent())) {
        if (parentScrollView->isFrameView()) {
            const FrameView* parentView = toFrameView(parentScrollView);

            // Get our renderer in the parent view
            RenderPart* renderer = m_frame->ownerRenderer();
            if (!renderer)
                return parentRect;

            IntRect rect = parentView->convertToRenderer(*renderer, parentRect);
            // Subtract borders and padding
            rect.move(-renderer->borderLeft() - renderer->paddingLeft(),
                      -renderer->borderTop() - renderer->paddingTop());
            return rect;
        }

        return Widget::convertFromContainingView(parentRect);
    }

    return parentRect;
}

IntPoint FrameView::convertToContainingView(const IntPoint& localPoint) const
{
    if (const ScrollView* parentScrollView = toScrollView(parent())) {
        if (parentScrollView->isFrameView()) {
            const FrameView* parentView = toFrameView(parentScrollView);

            // Get our renderer in the parent view
            RenderPart* renderer = m_frame->ownerRenderer();
            if (!renderer)
                return localPoint;

            IntPoint point(localPoint);

            // Add borders and padding
            point.move(renderer->borderLeft() + renderer->paddingLeft(),
                       renderer->borderTop() + renderer->paddingTop());
            return parentView->convertFromRenderer(*renderer, point);
        }

        return Widget::convertToContainingView(localPoint);
    }

    return localPoint;
}

IntPoint FrameView::convertFromContainingView(const IntPoint& parentPoint) const
{
    if (const ScrollView* parentScrollView = toScrollView(parent())) {
        if (parentScrollView->isFrameView()) {
            const FrameView* parentView = toFrameView(parentScrollView);

            // Get our renderer in the parent view
            RenderPart* renderer = m_frame->ownerRenderer();
            if (!renderer)
                return parentPoint;

            IntPoint point = parentView->convertToRenderer(*renderer, parentPoint);
            // Subtract borders and padding
            point.move(-renderer->borderLeft() - renderer->paddingLeft(),
                       -renderer->borderTop() - renderer->paddingTop());
            return point;
        }

        return Widget::convertFromContainingView(parentPoint);
    }

    return parentPoint;
}

void FrameView::setTracksPaintInvalidations(bool trackPaintInvalidations)
{
    if (trackPaintInvalidations == m_isTrackingPaintInvalidations)
        return;

    for (Frame* frame = m_frame->tree().top(); frame; frame = frame->tree().traverseNext()) {
        if (!frame->isLocalFrame())
            continue;
        if (RenderView* renderView = toLocalFrame(frame)->contentRenderer())
            renderView->compositor()->setTracksRepaints(trackPaintInvalidations);
    }

    TRACE_EVENT_INSTANT1(TRACE_DISABLED_BY_DEFAULT("blink.invalidation"),
        "FrameView::setTracksPaintInvalidations", "enabled", trackPaintInvalidations);

    resetTrackedPaintInvalidations();
    m_isTrackingPaintInvalidations = trackPaintInvalidations;
}

void FrameView::resetTrackedPaintInvalidations()
{
    m_trackedPaintInvalidationRects.clear();
    if (RenderView* renderView = this->renderView())
        renderView->compositor()->resetTrackedRepaintRects();
}

String FrameView::trackedPaintInvalidationRectsAsText() const
{
    TextStream ts;
    if (!m_trackedPaintInvalidationRects.isEmpty()) {
        ts << "(repaint rects\n";
        for (size_t i = 0; i < m_trackedPaintInvalidationRects.size(); ++i)
            ts << "  (rect " << m_trackedPaintInvalidationRects[i].x() << " " << m_trackedPaintInvalidationRects[i].y() << " " << m_trackedPaintInvalidationRects[i].width() << " " << m_trackedPaintInvalidationRects[i].height() << ")\n";
        ts << ")\n";
    }
    return ts.release();
}

void FrameView::addResizerArea(RenderBox& resizerBox)
{
    if (!m_resizerAreas)
        m_resizerAreas = adoptPtr(new ResizerAreaSet);
    m_resizerAreas->add(&resizerBox);
}

void FrameView::removeResizerArea(RenderBox& resizerBox)
{
    if (!m_resizerAreas)
        return;

    ResizerAreaSet::iterator it = m_resizerAreas->find(&resizerBox);
    if (it != m_resizerAreas->end())
        m_resizerAreas->remove(it);
}

void FrameView::addScrollableArea(ScrollableArea* scrollableArea)
{
    ASSERT(scrollableArea);
    if (!m_scrollableAreas)
        m_scrollableAreas = adoptPtr(new ScrollableAreaSet);
    m_scrollableAreas->add(scrollableArea);
}

void FrameView::removeScrollableArea(ScrollableArea* scrollableArea)
{
    if (!m_scrollableAreas)
        return;
    m_scrollableAreas->remove(scrollableArea);
}

void FrameView::removeChild(Widget* widget)
{
    if (widget->isFrameView())
        removeScrollableArea(toFrameView(widget));

    ScrollView::removeChild(widget);
}

bool FrameView::wheelEvent(const PlatformWheelEvent& wheelEvent)
{
    bool allowScrolling = userInputScrollable(HorizontalScrollbar) || userInputScrollable(VerticalScrollbar);

    // Note that to allow for rubber-band over-scroll behavior, even non-scrollable views
    // should handle wheel events.
#if !USE(RUBBER_BANDING)
    if (!isScrollable())
        allowScrolling = false;
#endif

    if (allowScrolling && ScrollableArea::handleWheelEvent(wheelEvent))
        return true;

    // If the frame didn't handle the event, give the pinch-zoom viewport a chance to
    // process the scroll event.
    if (m_frame->settings()->pinchVirtualViewportEnabled() && m_frame->isMainFrame())
        return page()->frameHost().pinchViewport().handleWheelEvent(wheelEvent);

    return false;
}

bool FrameView::isVerticalDocument() const
{
    RenderView* renderView = this->renderView();
    if (!renderView)
        return true;

    return renderView->style()->isHorizontalWritingMode();
}

bool FrameView::isFlippedDocument() const
{
    RenderView* renderView = this->renderView();
    if (!renderView)
        return false;

    return renderView->style()->isFlippedBlocksWritingMode();
}

AXObjectCache* FrameView::axObjectCache() const
{
    if (frame().document())
        return frame().document()->existingAXObjectCache();
    return 0;
}

void FrameView::setCursor(const Cursor& cursor)
{
    Page* page = frame().page();
    if (!page || !page->settings().deviceSupportsMouse())
        return;
    page->chrome().setCursor(cursor);
}

void FrameView::frameRectsChanged()
{
    if (layoutSizeFixedToFrameSize())
        setLayoutSizeInternal(frameRect().size());

    ScrollView::frameRectsChanged();
}

void FrameView::setLayoutSizeInternal(const IntSize& size)
{
    if (m_layoutSize == size)
        return;

    m_layoutSize = size;
    contentsResized();
}

void FrameView::didAddScrollbar(Scrollbar* scrollbar, ScrollbarOrientation orientation)
{
    ScrollableArea::didAddScrollbar(scrollbar, orientation);
    if (AXObjectCache* cache = axObjectCache())
        cache->handleScrollbarUpdate(this);
}

void FrameView::willRemoveScrollbar(Scrollbar* scrollbar, ScrollbarOrientation orientation)
{
    ScrollableArea::willRemoveScrollbar(scrollbar, orientation);
    if (AXObjectCache* cache = axObjectCache()) {
        cache->remove(scrollbar);
        cache->handleScrollbarUpdate(this);
    }
}

} // namespace WebCore