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      1 // Copyright 2014 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #ifndef CONTENT_BROWSER_WEB_CONTENTS_AURA_OVERSCROLL_NAVIGATION_OVERLAY_H_
      6 #define CONTENT_BROWSER_WEB_CONTENTS_AURA_OVERSCROLL_NAVIGATION_OVERLAY_H_
      7 
      8 #include "base/gtest_prod_util.h"
      9 #include "base/macros.h"
     10 #include "content/browser/web_contents/aura/window_slider.h"
     11 #include "content/common/content_export.h"
     12 #include "content/public/browser/web_contents_observer.h"
     13 
     14 struct ViewHostMsg_UpdateRect_Params;
     15 
     16 namespace content {
     17 
     18 class ImageLayerDelegate;
     19 class ImageWindowDelegate;
     20 class OverscrollNavigationOverlayTest;
     21 
     22 // When a history navigation is triggered at the end of an overscroll
     23 // navigation, it is necessary to show the history-screenshot until the page is
     24 // done navigating and painting. This class accomplishes this by showing the
     25 // screenshot window on top of the page until the page has completed loading and
     26 // painting.
     27 class CONTENT_EXPORT OverscrollNavigationOverlay
     28     : public WebContentsObserver,
     29       public WindowSlider::Delegate {
     30  public:
     31   explicit OverscrollNavigationOverlay(WebContentsImpl* web_contents);
     32   virtual ~OverscrollNavigationOverlay();
     33 
     34   bool has_window() const { return !!window_.get(); }
     35 
     36   // Resets state and starts observing |web_contents_| for page load/paint
     37   // updates. This function makes sure that the screenshot window is stacked
     38   // on top, so that it hides the content window behind it, and destroys the
     39   // screenshot window when the page is done loading/painting.
     40   // This should be called immediately after initiating the navigation,
     41   // otherwise the overlay may be dismissed prematurely.
     42   void StartObserving();
     43 
     44   // Sets the screenshot window and the delegate. This takes ownership of
     45   // |window|.
     46   // Note that ImageWindowDelegate manages its own lifetime, so this function
     47   // does not take ownership of |delegate|.
     48   void SetOverlayWindow(scoped_ptr<aura::Window> window,
     49                         ImageWindowDelegate* delegate);
     50 
     51  private:
     52   friend class OverscrollNavigationOverlayTest;
     53   FRIEND_TEST_ALL_PREFIXES(OverscrollNavigationOverlayTest,
     54                            FirstVisuallyNonEmptyPaint_NoImage);
     55   FRIEND_TEST_ALL_PREFIXES(OverscrollNavigationOverlayTest,
     56                            FirstVisuallyNonEmptyPaint_WithImage);
     57   FRIEND_TEST_ALL_PREFIXES(OverscrollNavigationOverlayTest,
     58                            LoadUpdateWithoutNonEmptyPaint);
     59   FRIEND_TEST_ALL_PREFIXES(OverscrollNavigationOverlayTest,
     60                            MultiNavigation_LoadingUpdate);
     61   FRIEND_TEST_ALL_PREFIXES(OverscrollNavigationOverlayTest,
     62                            MultiNavigation_PaintUpdate);
     63 
     64   enum SlideDirection {
     65     SLIDE_UNKNOWN,
     66     SLIDE_BACK,
     67     SLIDE_FRONT
     68   };
     69 
     70   // Stop observing the page and start the final overlay fade-out animation if
     71   // a window-slide isn't in progress and either the page has been painted or
     72   // the page-load has completed.
     73   void StopObservingIfDone();
     74 
     75   // Creates a layer to be used for window-slide. |offset| is the offset of the
     76   // NavigationEntry for the screenshot image to display.
     77   ui::Layer* CreateSlideLayer(int offset);
     78 
     79   // Overridden from WindowSlider::Delegate:
     80   virtual ui::Layer* CreateBackLayer() OVERRIDE;
     81   virtual ui::Layer* CreateFrontLayer() OVERRIDE;
     82   virtual void OnWindowSlideCompleting() OVERRIDE;
     83   virtual void OnWindowSlideCompleted(scoped_ptr<ui::Layer> layer) OVERRIDE;
     84   virtual void OnWindowSlideAborted() OVERRIDE;
     85   virtual void OnWindowSliderDestroyed() OVERRIDE;
     86 
     87   // Overridden from WebContentsObserver:
     88   virtual void DidFirstVisuallyNonEmptyPaint() OVERRIDE;
     89   virtual void DidStopLoading(RenderViewHost* host) OVERRIDE;
     90 
     91   // The WebContents which is being navigated.
     92   WebContentsImpl* web_contents_;
     93 
     94   // The screenshot overlay window.
     95   scoped_ptr<aura::Window> window_;
     96 
     97   // This is the WindowDelegate of |window_|. The delegate manages its own
     98   // lifetime (destroys itself when |window_| is destroyed).
     99   ImageWindowDelegate* image_delegate_;
    100 
    101   bool loading_complete_;
    102   bool received_paint_update_;
    103 
    104   // Unique ID of the NavigationEntry we are navigating to. This is needed to
    105   // filter on WebContentsObserver callbacks and is used to dismiss the overlay
    106   // when the relevant page loads and paints.
    107   int pending_entry_id_;
    108 
    109   // The |WindowSlider| that allows sliding history layers while the page is
    110   // being reloaded.
    111   scoped_ptr<WindowSlider> window_slider_;
    112 
    113   // Layer to be used for the final overlay fadeout animation when the overlay
    114   // is being dismissed.
    115   scoped_ptr<ui::Layer> overlay_dismiss_layer_;
    116 
    117   // The direction of the in-progress slide (if any).
    118   SlideDirection slide_direction_;
    119 
    120   // The LayerDelegate used for the back/front layers during a slide.
    121   scoped_ptr<ImageLayerDelegate> layer_delegate_;
    122 
    123   DISALLOW_COPY_AND_ASSIGN(OverscrollNavigationOverlay);
    124 };
    125 
    126 }  // namespace content
    127 
    128 #endif  // CONTENT_BROWSER_WEB_CONTENTS_AURA_OVERSCROLL_NAVIGATION_OVERLAY_H_
    129