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      1 // Copyright 2011 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 CC_LAYERS_LAYER_IMPL_H_
      6 #define CC_LAYERS_LAYER_IMPL_H_
      7 
      8 #include <set>
      9 #include <string>
     10 
     11 #include "base/logging.h"
     12 #include "base/memory/scoped_ptr.h"
     13 #include "base/values.h"
     14 #include "cc/animation/layer_animation_controller.h"
     15 #include "cc/animation/layer_animation_value_observer.h"
     16 #include "cc/animation/layer_animation_value_provider.h"
     17 #include "cc/base/cc_export.h"
     18 #include "cc/base/region.h"
     19 #include "cc/base/scoped_ptr_vector.h"
     20 #include "cc/input/input_handler.h"
     21 #include "cc/layers/draw_properties.h"
     22 #include "cc/layers/layer_lists.h"
     23 #include "cc/layers/layer_position_constraint.h"
     24 #include "cc/layers/render_surface_impl.h"
     25 #include "cc/output/filter_operations.h"
     26 #include "cc/quads/render_pass.h"
     27 #include "cc/quads/shared_quad_state.h"
     28 #include "cc/resources/resource_provider.h"
     29 #include "skia/ext/refptr.h"
     30 #include "third_party/skia/include/core/SkColor.h"
     31 #include "third_party/skia/include/core/SkImageFilter.h"
     32 #include "third_party/skia/include/core/SkPicture.h"
     33 #include "ui/gfx/point3_f.h"
     34 #include "ui/gfx/rect.h"
     35 #include "ui/gfx/rect_f.h"
     36 #include "ui/gfx/transform.h"
     37 
     38 namespace base {
     39 namespace debug {
     40 class ConvertableToTraceFormat;
     41 }
     42 
     43 class DictionaryValue;
     44 }
     45 
     46 namespace cc {
     47 
     48 class LayerTreeHostImpl;
     49 class LayerTreeImpl;
     50 class MicroBenchmarkImpl;
     51 class QuadSink;
     52 class Renderer;
     53 class ScrollbarAnimationController;
     54 class ScrollbarLayerImplBase;
     55 class Tile;
     56 
     57 struct AppendQuadsData;
     58 
     59 enum DrawMode {
     60   DRAW_MODE_NONE,
     61   DRAW_MODE_HARDWARE,
     62   DRAW_MODE_SOFTWARE,
     63   DRAW_MODE_RESOURCELESS_SOFTWARE
     64 };
     65 
     66 class CC_EXPORT LayerImpl : public LayerAnimationValueObserver,
     67                             public LayerAnimationValueProvider {
     68  public:
     69   // Allows for the ownership of the total scroll offset to be delegated outside
     70   // of the layer.
     71   class ScrollOffsetDelegate {
     72    public:
     73     virtual void SetTotalScrollOffset(const gfx::Vector2dF& new_value) = 0;
     74     virtual gfx::Vector2dF GetTotalScrollOffset() = 0;
     75     virtual bool IsExternalFlingActive() const = 0;
     76   };
     77 
     78   typedef LayerImplList RenderSurfaceListType;
     79   typedef LayerImplList LayerListType;
     80   typedef RenderSurfaceImpl RenderSurfaceType;
     81 
     82   enum RenderingContextConstants { NO_RENDERING_CONTEXT = 0 };
     83 
     84   static scoped_ptr<LayerImpl> Create(LayerTreeImpl* tree_impl, int id) {
     85     return make_scoped_ptr(new LayerImpl(tree_impl, id));
     86   }
     87 
     88   virtual ~LayerImpl();
     89 
     90   int id() const { return layer_id_; }
     91 
     92   // LayerAnimationValueProvider implementation.
     93   virtual gfx::Vector2dF ScrollOffsetForAnimation() const OVERRIDE;
     94 
     95   // LayerAnimationValueObserver implementation.
     96   virtual void OnFilterAnimated(const FilterOperations& filters) OVERRIDE;
     97   virtual void OnOpacityAnimated(float opacity) OVERRIDE;
     98   virtual void OnTransformAnimated(const gfx::Transform& transform) OVERRIDE;
     99   virtual void OnScrollOffsetAnimated(
    100       const gfx::Vector2dF& scroll_offset) OVERRIDE;
    101   virtual void OnAnimationWaitingForDeletion() OVERRIDE;
    102   virtual bool IsActive() const OVERRIDE;
    103 
    104   // Tree structure.
    105   LayerImpl* parent() { return parent_; }
    106   const LayerImpl* parent() const { return parent_; }
    107   const OwnedLayerImplList& children() const { return children_; }
    108   OwnedLayerImplList& children() { return children_; }
    109   LayerImpl* child_at(size_t index) const { return children_[index]; }
    110   void AddChild(scoped_ptr<LayerImpl> child);
    111   scoped_ptr<LayerImpl> RemoveChild(LayerImpl* child);
    112   void SetParent(LayerImpl* parent);
    113 
    114   // Warning: This does not preserve tree structure invariants.
    115   void ClearChildList();
    116 
    117   bool HasAncestor(const LayerImpl* ancestor) const;
    118 
    119   void SetScrollParent(LayerImpl* parent);
    120 
    121   LayerImpl* scroll_parent() { return scroll_parent_; }
    122   const LayerImpl* scroll_parent() const { return scroll_parent_; }
    123 
    124   void SetScrollChildren(std::set<LayerImpl*>* children);
    125 
    126   std::set<LayerImpl*>* scroll_children() { return scroll_children_.get(); }
    127   const std::set<LayerImpl*>* scroll_children() const {
    128     return scroll_children_.get();
    129   }
    130 
    131   void SetClipParent(LayerImpl* ancestor);
    132 
    133   LayerImpl* clip_parent() {
    134     return clip_parent_;
    135   }
    136   const LayerImpl* clip_parent() const {
    137     return clip_parent_;
    138   }
    139 
    140   void SetClipChildren(std::set<LayerImpl*>* children);
    141 
    142   std::set<LayerImpl*>* clip_children() { return clip_children_.get(); }
    143   const std::set<LayerImpl*>* clip_children() const {
    144     return clip_children_.get();
    145   }
    146 
    147   void PassCopyRequests(ScopedPtrVector<CopyOutputRequest>* requests);
    148   // Can only be called when the layer has a copy request.
    149   void TakeCopyRequestsAndTransformToTarget(
    150       ScopedPtrVector<CopyOutputRequest>* request);
    151   bool HasCopyRequest() const { return !copy_requests_.empty(); }
    152 
    153   void SetMaskLayer(scoped_ptr<LayerImpl> mask_layer);
    154   LayerImpl* mask_layer() { return mask_layer_.get(); }
    155   const LayerImpl* mask_layer() const { return mask_layer_.get(); }
    156   scoped_ptr<LayerImpl> TakeMaskLayer();
    157 
    158   void SetReplicaLayer(scoped_ptr<LayerImpl> replica_layer);
    159   LayerImpl* replica_layer() { return replica_layer_.get(); }
    160   const LayerImpl* replica_layer() const { return replica_layer_.get(); }
    161   scoped_ptr<LayerImpl> TakeReplicaLayer();
    162 
    163   bool has_mask() const { return mask_layer_; }
    164   bool has_replica() const { return replica_layer_; }
    165   bool replica_has_mask() const {
    166     return replica_layer_ && (mask_layer_ || replica_layer_->mask_layer_);
    167   }
    168 
    169   LayerTreeImpl* layer_tree_impl() const { return layer_tree_impl_; }
    170 
    171   void PopulateSharedQuadState(SharedQuadState* state) const;
    172   // WillDraw must be called before AppendQuads. If WillDraw returns false,
    173   // AppendQuads and DidDraw will not be called. If WillDraw returns true,
    174   // DidDraw is guaranteed to be called before another WillDraw or before
    175   // the layer is destroyed. To enforce this, any class that overrides
    176   // WillDraw/DidDraw must call the base class version only if WillDraw
    177   // returns true.
    178   virtual bool WillDraw(DrawMode draw_mode,
    179                         ResourceProvider* resource_provider);
    180   virtual void AppendQuads(QuadSink* quad_sink,
    181                            AppendQuadsData* append_quads_data) {}
    182   virtual void DidDraw(ResourceProvider* resource_provider);
    183 
    184   virtual ResourceProvider::ResourceId ContentsResourceId() const;
    185 
    186   virtual bool HasDelegatedContent() const;
    187   virtual bool HasContributingDelegatedRenderPasses() const;
    188   virtual RenderPass::Id FirstContributingRenderPassId() const;
    189   virtual RenderPass::Id NextContributingRenderPassId(RenderPass::Id id) const;
    190 
    191   virtual void UpdateTiles() {}
    192   virtual void NotifyTileStateChanged(const Tile* tile) {}
    193 
    194   virtual ScrollbarLayerImplBase* ToScrollbarLayer();
    195 
    196   // Returns true if this layer has content to draw.
    197   void SetDrawsContent(bool draws_content);
    198   bool DrawsContent() const { return draws_content_; }
    199 
    200   void SetHideLayerAndSubtree(bool hide);
    201   bool hide_layer_and_subtree() const { return hide_layer_and_subtree_; }
    202 
    203   bool force_render_surface() const { return force_render_surface_; }
    204   void SetForceRenderSurface(bool force) { force_render_surface_ = force; }
    205 
    206   void SetTransformOrigin(const gfx::Point3F& transform_origin);
    207   gfx::Point3F transform_origin() const { return transform_origin_; }
    208 
    209   void SetBackgroundColor(SkColor background_color);
    210   SkColor background_color() const { return background_color_; }
    211   // If contents_opaque(), return an opaque color else return a
    212   // non-opaque color.  Tries to return background_color(), if possible.
    213   SkColor SafeOpaqueBackgroundColor() const;
    214 
    215   void SetFilters(const FilterOperations& filters);
    216   const FilterOperations& filters() const { return filters_; }
    217   bool FilterIsAnimating() const;
    218   bool FilterIsAnimatingOnImplOnly() const;
    219 
    220   void SetBackgroundFilters(const FilterOperations& filters);
    221   const FilterOperations& background_filters() const {
    222     return background_filters_;
    223   }
    224 
    225   void SetMasksToBounds(bool masks_to_bounds);
    226   bool masks_to_bounds() const { return masks_to_bounds_; }
    227 
    228   void SetContentsOpaque(bool opaque);
    229   bool contents_opaque() const { return contents_opaque_; }
    230 
    231   void SetOpacity(float opacity);
    232   float opacity() const { return opacity_; }
    233   bool OpacityIsAnimating() const;
    234   bool OpacityIsAnimatingOnImplOnly() const;
    235 
    236   void SetBlendMode(SkXfermode::Mode);
    237   SkXfermode::Mode blend_mode() const { return blend_mode_; }
    238   bool uses_default_blend_mode() const {
    239     return blend_mode_ == SkXfermode::kSrcOver_Mode;
    240   }
    241 
    242   void SetIsRootForIsolatedGroup(bool root);
    243   bool is_root_for_isolated_group() const {
    244     return is_root_for_isolated_group_;
    245   }
    246 
    247   void SetPosition(const gfx::PointF& position);
    248   gfx::PointF position() const { return position_; }
    249 
    250   void SetIsContainerForFixedPositionLayers(bool container) {
    251     is_container_for_fixed_position_layers_ = container;
    252   }
    253   // This is a non-trivial function in Layer.
    254   bool IsContainerForFixedPositionLayers() const {
    255     return is_container_for_fixed_position_layers_;
    256   }
    257 
    258   gfx::Vector2dF FixedContainerSizeDelta() const;
    259 
    260   void SetPositionConstraint(const LayerPositionConstraint& constraint) {
    261     position_constraint_ = constraint;
    262   }
    263   const LayerPositionConstraint& position_constraint() const {
    264     return position_constraint_;
    265   }
    266 
    267   void SetShouldFlattenTransform(bool flatten);
    268   bool should_flatten_transform() const { return should_flatten_transform_; }
    269 
    270   bool Is3dSorted() const { return sorting_context_id_ != 0; }
    271 
    272   void SetUseParentBackfaceVisibility(bool use) {
    273     use_parent_backface_visibility_ = use;
    274   }
    275   bool use_parent_backface_visibility() const {
    276     return use_parent_backface_visibility_;
    277   }
    278 
    279   bool ShowDebugBorders() const;
    280 
    281   // These invalidate the host's render surface layer list.  The caller
    282   // is responsible for calling set_needs_update_draw_properties on the tree
    283   // so that its list can be recreated.
    284   void CreateRenderSurface();
    285   void ClearRenderSurface();
    286   void ClearRenderSurfaceLayerList();
    287 
    288   DrawProperties<LayerImpl>& draw_properties() {
    289     return draw_properties_;
    290   }
    291   const DrawProperties<LayerImpl>& draw_properties() const {
    292     return draw_properties_;
    293   }
    294 
    295   // The following are shortcut accessors to get various information from
    296   // draw_properties_
    297   const gfx::Transform& draw_transform() const {
    298     return draw_properties_.target_space_transform;
    299   }
    300   const gfx::Transform& screen_space_transform() const {
    301     return draw_properties_.screen_space_transform;
    302   }
    303   float draw_opacity() const { return draw_properties_.opacity; }
    304   bool draw_opacity_is_animating() const {
    305     return draw_properties_.opacity_is_animating;
    306   }
    307   bool draw_transform_is_animating() const {
    308     return draw_properties_.target_space_transform_is_animating;
    309   }
    310   bool screen_space_transform_is_animating() const {
    311     return draw_properties_.screen_space_transform_is_animating;
    312   }
    313   bool screen_space_opacity_is_animating() const {
    314     return draw_properties_.screen_space_opacity_is_animating;
    315   }
    316   bool can_use_lcd_text() const { return draw_properties_.can_use_lcd_text; }
    317   bool is_clipped() const { return draw_properties_.is_clipped; }
    318   gfx::Rect clip_rect() const { return draw_properties_.clip_rect; }
    319   gfx::Rect drawable_content_rect() const {
    320     return draw_properties_.drawable_content_rect;
    321   }
    322   gfx::Rect visible_content_rect() const {
    323     return draw_properties_.visible_content_rect;
    324   }
    325   LayerImpl* render_target() {
    326     DCHECK(!draw_properties_.render_target ||
    327            draw_properties_.render_target->render_surface());
    328     return draw_properties_.render_target;
    329   }
    330   const LayerImpl* render_target() const {
    331     DCHECK(!draw_properties_.render_target ||
    332            draw_properties_.render_target->render_surface());
    333     return draw_properties_.render_target;
    334   }
    335   RenderSurfaceImpl* render_surface() const {
    336     return draw_properties_.render_surface.get();
    337   }
    338   int num_unclipped_descendants() const {
    339     return draw_properties_.num_unclipped_descendants;
    340   }
    341 
    342   // The client should be responsible for setting bounds, content bounds and
    343   // contents scale to appropriate values. LayerImpl doesn't calculate any of
    344   // them from the other values.
    345 
    346   void SetBounds(const gfx::Size& bounds);
    347   void SetTemporaryImplBounds(const gfx::SizeF& bounds);
    348   gfx::Size bounds() const;
    349   gfx::Vector2dF BoundsDelta() const {
    350     return gfx::Vector2dF(temporary_impl_bounds_.width() - bounds_.width(),
    351                           temporary_impl_bounds_.height() - bounds_.height());
    352   }
    353 
    354   void SetContentBounds(const gfx::Size& content_bounds);
    355   gfx::Size content_bounds() const { return draw_properties_.content_bounds; }
    356 
    357   float contents_scale_x() const { return draw_properties_.contents_scale_x; }
    358   float contents_scale_y() const { return draw_properties_.contents_scale_y; }
    359   void SetContentsScale(float contents_scale_x, float contents_scale_y);
    360 
    361   void SetScrollOffsetDelegate(ScrollOffsetDelegate* scroll_offset_delegate);
    362   bool IsExternalFlingActive() const;
    363 
    364   void SetScrollOffset(const gfx::Vector2d& scroll_offset);
    365   void SetScrollOffsetAndDelta(const gfx::Vector2d& scroll_offset,
    366                                const gfx::Vector2dF& scroll_delta);
    367   gfx::Vector2d scroll_offset() const { return scroll_offset_; }
    368 
    369   gfx::Vector2d MaxScrollOffset() const;
    370   gfx::Vector2dF ClampScrollToMaxScrollOffset();
    371   void SetScrollbarPosition(ScrollbarLayerImplBase* scrollbar_layer,
    372                             LayerImpl* scrollbar_clip_layer) const;
    373   void SetScrollDelta(const gfx::Vector2dF& scroll_delta);
    374   gfx::Vector2dF ScrollDelta() const;
    375 
    376   gfx::Vector2dF TotalScrollOffset() const;
    377 
    378   void SetSentScrollDelta(const gfx::Vector2d& sent_scroll_delta);
    379   gfx::Vector2d sent_scroll_delta() const { return sent_scroll_delta_; }
    380 
    381   // Returns the delta of the scroll that was outside of the bounds of the
    382   // initial scroll
    383   gfx::Vector2dF ScrollBy(const gfx::Vector2dF& scroll);
    384 
    385   void SetScrollClipLayer(int scroll_clip_layer_id);
    386   LayerImpl* scroll_clip_layer() const { return scroll_clip_layer_; }
    387   bool scrollable() const { return !!scroll_clip_layer_; }
    388 
    389   void set_user_scrollable_horizontal(bool scrollable) {
    390     user_scrollable_horizontal_ = scrollable;
    391   }
    392   void set_user_scrollable_vertical(bool scrollable) {
    393     user_scrollable_vertical_ = scrollable;
    394   }
    395 
    396   void ApplySentScrollDeltasFromAbortedCommit();
    397   void ApplyScrollDeltasSinceBeginMainFrame();
    398 
    399   void SetShouldScrollOnMainThread(bool should_scroll_on_main_thread) {
    400     should_scroll_on_main_thread_ = should_scroll_on_main_thread;
    401   }
    402   bool should_scroll_on_main_thread() const {
    403     return should_scroll_on_main_thread_;
    404   }
    405 
    406   void SetHaveWheelEventHandlers(bool have_wheel_event_handlers) {
    407     have_wheel_event_handlers_ = have_wheel_event_handlers;
    408   }
    409   bool have_wheel_event_handlers() const { return have_wheel_event_handlers_; }
    410 
    411   void SetHaveScrollEventHandlers(bool have_scroll_event_handlers) {
    412     have_scroll_event_handlers_ = have_scroll_event_handlers;
    413   }
    414   bool have_scroll_event_handlers() const {
    415     return have_scroll_event_handlers_;
    416   }
    417 
    418   void SetNonFastScrollableRegion(const Region& region) {
    419     non_fast_scrollable_region_ = region;
    420   }
    421   const Region& non_fast_scrollable_region() const {
    422     return non_fast_scrollable_region_;
    423   }
    424 
    425   void SetTouchEventHandlerRegion(const Region& region) {
    426     touch_event_handler_region_ = region;
    427   }
    428   const Region& touch_event_handler_region() const {
    429     return touch_event_handler_region_;
    430   }
    431 
    432   void SetDrawCheckerboardForMissingTiles(bool checkerboard) {
    433     draw_checkerboard_for_missing_tiles_ = checkerboard;
    434   }
    435   bool draw_checkerboard_for_missing_tiles() const {
    436     return draw_checkerboard_for_missing_tiles_;
    437   }
    438 
    439   InputHandler::ScrollStatus TryScroll(
    440       const gfx::PointF& screen_space_point,
    441       InputHandler::ScrollInputType type) const;
    442 
    443   void SetDoubleSided(bool double_sided);
    444   bool double_sided() const { return double_sided_; }
    445 
    446   void SetTransform(const gfx::Transform& transform);
    447   const gfx::Transform& transform() const { return transform_; }
    448   bool TransformIsAnimating() const;
    449   bool TransformIsAnimatingOnImplOnly() const;
    450   void SetTransformAndInvertibility(const gfx::Transform& transform,
    451                                     bool transform_is_invertible);
    452   bool transform_is_invertible() const { return transform_is_invertible_; }
    453 
    454   // Note this rect is in layer space (not content space).
    455   void SetUpdateRect(const gfx::RectF& update_rect);
    456 
    457   const gfx::RectF& update_rect() const { return update_rect_; }
    458 
    459   void AddDamageRect(const gfx::RectF& damage_rect);
    460 
    461   const gfx::RectF& damage_rect() const { return damage_rect_; }
    462 
    463   virtual base::DictionaryValue* LayerTreeAsJson() const;
    464 
    465   void SetStackingOrderChanged(bool stacking_order_changed);
    466 
    467   bool LayerPropertyChanged() const { return layer_property_changed_; }
    468 
    469   void ResetAllChangeTrackingForSubtree();
    470 
    471   LayerAnimationController* layer_animation_controller() {
    472     return layer_animation_controller_.get();
    473   }
    474 
    475   const LayerAnimationController* layer_animation_controller() const {
    476     return layer_animation_controller_.get();
    477   }
    478 
    479   virtual Region VisibleContentOpaqueRegion() const;
    480 
    481   virtual void DidBecomeActive();
    482 
    483   virtual void DidBeginTracing();
    484 
    485   // Release resources held by this layer. Called when the output surface
    486   // that rendered this layer was lost or a rendering mode switch has occured.
    487   virtual void ReleaseResources();
    488 
    489   ScrollbarAnimationController* scrollbar_animation_controller() const {
    490     return scrollbar_animation_controller_.get();
    491   }
    492 
    493   typedef std::set<ScrollbarLayerImplBase*> ScrollbarSet;
    494   ScrollbarSet* scrollbars() { return scrollbars_.get(); }
    495   void ClearScrollbars();
    496   void AddScrollbar(ScrollbarLayerImplBase* layer);
    497   void RemoveScrollbar(ScrollbarLayerImplBase* layer);
    498   bool HasScrollbar(ScrollbarOrientation orientation) const;
    499   void ScrollbarParametersDidChange();
    500   int clip_height() {
    501     return scroll_clip_layer_ ? scroll_clip_layer_->bounds().height() : 0;
    502   }
    503 
    504   gfx::Rect LayerRectToContentRect(const gfx::RectF& layer_rect) const;
    505 
    506   virtual skia::RefPtr<SkPicture> GetPicture();
    507 
    508   virtual scoped_ptr<LayerImpl> CreateLayerImpl(LayerTreeImpl* tree_impl);
    509   virtual void PushPropertiesTo(LayerImpl* layer);
    510 
    511   virtual void GetAllTilesForTracing(std::set<const Tile*>* tiles) const;
    512   scoped_ptr<base::Value> AsValue() const;
    513   virtual size_t GPUMemoryUsageInBytes() const;
    514 
    515   void SetNeedsPushProperties();
    516   void AddDependentNeedsPushProperties();
    517   void RemoveDependentNeedsPushProperties();
    518   bool parent_should_know_need_push_properties() const {
    519     return needs_push_properties() || descendant_needs_push_properties();
    520   }
    521 
    522   bool needs_push_properties() const { return needs_push_properties_; }
    523   bool descendant_needs_push_properties() const {
    524     return num_dependents_need_push_properties_ > 0;
    525   }
    526 
    527   virtual void RunMicroBenchmark(MicroBenchmarkImpl* benchmark);
    528 
    529   virtual void SetDebugInfo(
    530       scoped_refptr<base::debug::ConvertableToTraceFormat> other);
    531 
    532   bool IsDrawnRenderSurfaceLayerListMember() const;
    533 
    534   void Set3dSortingContextId(int id);
    535   int sorting_context_id() { return sorting_context_id_; }
    536 
    537  protected:
    538   LayerImpl(LayerTreeImpl* layer_impl, int id);
    539 
    540   // Get the color and size of the layer's debug border.
    541   virtual void GetDebugBorderProperties(SkColor* color, float* width) const;
    542 
    543   void AppendDebugBorderQuad(QuadSink* quad_sink,
    544                              const gfx::Size& content_bounds,
    545                              const SharedQuadState* shared_quad_state,
    546                              AppendQuadsData* append_quads_data) const;
    547   void AppendDebugBorderQuad(QuadSink* quad_sink,
    548                              const gfx::Size& content_bounds,
    549                              const SharedQuadState* shared_quad_state,
    550                              AppendQuadsData* append_quads_data,
    551                              SkColor color,
    552                              float width) const;
    553 
    554   virtual void AsValueInto(base::DictionaryValue* dict) const;
    555 
    556   void NoteLayerPropertyChanged();
    557   void NoteLayerPropertyChangedForSubtree();
    558 
    559   // Note carefully this does not affect the current layer.
    560   void NoteLayerPropertyChangedForDescendants();
    561 
    562  private:
    563   void NoteLayerPropertyChangedForDescendantsInternal();
    564 
    565   virtual const char* LayerTypeAsString() const;
    566 
    567   // Properties internal to LayerImpl
    568   LayerImpl* parent_;
    569   OwnedLayerImplList children_;
    570 
    571   LayerImpl* scroll_parent_;
    572 
    573   // Storing a pointer to a set rather than a set since this will be rarely
    574   // used. If this pointer turns out to be too heavy, we could have this (and
    575   // the scroll parent above) be stored in a LayerImpl -> scroll_info
    576   // map somewhere.
    577   scoped_ptr<std::set<LayerImpl*> > scroll_children_;
    578 
    579   LayerImpl* clip_parent_;
    580   scoped_ptr<std::set<LayerImpl*> > clip_children_;
    581 
    582   // mask_layer_ can be temporarily stolen during tree sync, we need this ID to
    583   // confirm newly assigned layer is still the previous one
    584   int mask_layer_id_;
    585   scoped_ptr<LayerImpl> mask_layer_;
    586   int replica_layer_id_;  // ditto
    587   scoped_ptr<LayerImpl> replica_layer_;
    588   int layer_id_;
    589   LayerTreeImpl* layer_tree_impl_;
    590 
    591   // Properties synchronized from the associated Layer.
    592   gfx::Point3F transform_origin_;
    593   gfx::Size bounds_;
    594   gfx::SizeF temporary_impl_bounds_;
    595   gfx::Vector2d scroll_offset_;
    596   ScrollOffsetDelegate* scroll_offset_delegate_;
    597   LayerImpl* scroll_clip_layer_;
    598   bool scrollable_ : 1;
    599   bool should_scroll_on_main_thread_ : 1;
    600   bool have_wheel_event_handlers_ : 1;
    601   bool have_scroll_event_handlers_ : 1;
    602   bool user_scrollable_horizontal_ : 1;
    603   bool user_scrollable_vertical_ : 1;
    604   bool stacking_order_changed_ : 1;
    605   // Whether the "back" of this layer should draw.
    606   bool double_sided_ : 1;
    607   bool should_flatten_transform_ : 1;
    608 
    609   // Tracks if drawing-related properties have changed since last redraw.
    610   bool layer_property_changed_ : 1;
    611 
    612   bool masks_to_bounds_ : 1;
    613   bool contents_opaque_ : 1;
    614   bool is_root_for_isolated_group_ : 1;
    615   bool use_parent_backface_visibility_ : 1;
    616   bool draw_checkerboard_for_missing_tiles_ : 1;
    617   bool draws_content_ : 1;
    618   bool hide_layer_and_subtree_ : 1;
    619   bool force_render_surface_ : 1;
    620 
    621   // Cache transform_'s invertibility.
    622   bool transform_is_invertible_ : 1;
    623 
    624   // Set for the layer that other layers are fixed to.
    625   bool is_container_for_fixed_position_layers_ : 1;
    626   Region non_fast_scrollable_region_;
    627   Region touch_event_handler_region_;
    628   SkColor background_color_;
    629 
    630   float opacity_;
    631   SkXfermode::Mode blend_mode_;
    632   gfx::PointF position_;
    633   gfx::Transform transform_;
    634 
    635   LayerPositionConstraint position_constraint_;
    636 
    637   gfx::Vector2dF scroll_delta_;
    638   gfx::Vector2d sent_scroll_delta_;
    639   gfx::Vector2dF last_scroll_offset_;
    640 
    641   // The global depth value of the center of the layer. This value is used
    642   // to sort layers from back to front.
    643   float draw_depth_;
    644 
    645   FilterOperations filters_;
    646   FilterOperations background_filters_;
    647 
    648  protected:
    649   friend class TreeSynchronizer;
    650 
    651   // This flag is set when the layer needs to push properties to the active
    652   // side.
    653   bool needs_push_properties_;
    654 
    655   // The number of direct children or dependent layers that need to be recursed
    656   // to in order for them or a descendent of them to push properties to the
    657   // active side.
    658   int num_dependents_need_push_properties_;
    659 
    660   // Layers that share a sorting context id will be sorted together in 3d
    661   // space.  0 is a special value that means this layer will not be sorted and
    662   // will be drawn in paint order.
    663   int sorting_context_id_;
    664 
    665   DrawMode current_draw_mode_;
    666 
    667  private:
    668   // Rect indicating what was repainted/updated during update.
    669   // Note that plugin layers bypass this and leave it empty.
    670   // Uses layer (not content) space.
    671   gfx::RectF update_rect_;
    672 
    673   // This rect is in layer space.
    674   gfx::RectF damage_rect_;
    675 
    676   // Manages animations for this layer.
    677   scoped_refptr<LayerAnimationController> layer_animation_controller_;
    678 
    679   // Manages scrollbars for this layer
    680   scoped_ptr<ScrollbarAnimationController> scrollbar_animation_controller_;
    681 
    682   scoped_ptr<ScrollbarSet> scrollbars_;
    683 
    684   ScopedPtrVector<CopyOutputRequest> copy_requests_;
    685 
    686   // Group of properties that need to be computed based on the layer tree
    687   // hierarchy before layers can be drawn.
    688   DrawProperties<LayerImpl> draw_properties_;
    689 
    690   scoped_refptr<base::debug::ConvertableToTraceFormat> debug_info_;
    691 
    692   DISALLOW_COPY_AND_ASSIGN(LayerImpl);
    693 };
    694 
    695 }  // namespace cc
    696 
    697 #endif  // CC_LAYERS_LAYER_IMPL_H_
    698