cc/layers/layer.h

   1 // Copyright 2010 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_H_
   6 #define CC_LAYERS_LAYER_H_
   7
   8 #include <set>
   9 #include <string>
  10 #include <vector>
  11
  12 #include "base/callback.h"
  13 #include "base/memory/ref_counted.h"
  14 #include "base/observer_list.h"
  15 #include "cc/animation/layer_animation_controller.h"
  16 #include "cc/animation/layer_animation_value_observer.h"
  17 #include "cc/animation/layer_animation_value_provider.h"
  18 #include "cc/base/cc_export.h"
  19 #include "cc/base/region.h"
  20 #include "cc/base/scoped_ptr_vector.h"
  21 #include "cc/debug/frame_timing_request.h"
  22 #include "cc/debug/micro_benchmark.h"
  23 #include "cc/layers/draw_properties.h"
  24 #include "cc/layers/layer_lists.h"
  25 #include "cc/layers/layer_position_constraint.h"
  26 #include "cc/layers/paint_properties.h"
  27 #include "cc/layers/render_surface.h"
  28 #include "cc/layers/scroll_blocks_on.h"
  29 #include "cc/output/filter_operations.h"
  30 #include "cc/trees/property_tree.h"
  31 #include "skia/ext/refptr.h"
  32 #include "third_party/skia/include/core/SkColor.h"
  33 #include "third_party/skia/include/core/SkImageFilter.h"
  34 #include "third_party/skia/include/core/SkPicture.h"
  35 #include "third_party/skia/include/core/SkXfermode.h"
  36 #include "ui/gfx/geometry/point3_f.h"
  37 #include "ui/gfx/geometry/rect.h"
  38 #include "ui/gfx/geometry/rect_f.h"
  39 #include "ui/gfx/geometry/scroll_offset.h"
  40 #include "ui/gfx/transform.h"
  41
  42 namespace gfx {
  43 class BoxF;
  44 }
  45
  46 namespace base {
  47 namespace trace_event {
  48 class ConvertableToTraceFormat;
  49 }
  50 }
  51
  52 namespace cc {
  53
  54 class Animation;
  55 class AnimationDelegate;
  56 struct AnimationEvent;
  57 class CopyOutputRequest;
  58 class LayerAnimationDelegate;
  59 class LayerAnimationEventObserver;
  60 class LayerClient;
  61 class LayerImpl;
  62 class LayerTreeHost;
  63 class LayerTreeHostCommon;
  64 class LayerTreeImpl;
  65 class PriorityCalculator;
  66 class RenderingStatsInstrumentation;
  67 class ResourceUpdateQueue;
  68 class ScrollbarLayerInterface;
  69 class SimpleEnclosedRegion;
  70 struct AnimationEvent;
  71 template <typename LayerType>
  72 class OcclusionTracker;
  73
  74 // Base class for composited layers. Special layer types are derived from
  75 // this class.
  76 class CC_EXPORT Layer : public base::RefCounted<Layer>,
  77                         public LayerAnimationValueObserver,
  78                         public LayerAnimationValueProvider {
  79  public:
  80   typedef RenderSurfaceLayerList RenderSurfaceListType;
  81   typedef LayerList LayerListType;
  82   typedef RenderSurface RenderSurfaceType;
  83
  84   enum LayerIdLabels {
  85     INVALID_ID = -1,
  86   };
  87
  88   static scoped_refptr<Layer> Create();
  89
  90   int id() const { return layer_id_; }
  91
  92   Layer* RootLayer();
  93   Layer* parent() { return parent_; }
  94   const Layer* parent() const { return parent_; }
  95   void AddChild(scoped_refptr<Layer> child);
  96   void InsertChild(scoped_refptr<Layer> child, size_t index);
  97   void ReplaceChild(Layer* reference, scoped_refptr<Layer> new_layer);
  98   void RemoveFromParent();
  99   void RemoveAllChildren();
 100   void SetChildren(const LayerList& children);
 101   bool HasAncestor(const Layer* ancestor) const;
 102
 103   const LayerList& children() const { return children_; }
 104   Layer* child_at(size_t index) { return children_[index].get(); }
 105
 106   // This requests the layer and its subtree be rendered and given to the
 107   // callback. If the copy is unable to be produced (the layer is destroyed
 108   // first), then the callback is called with a nullptr/empty result.
 109   void RequestCopyOfOutput(scoped_ptr<CopyOutputRequest> request);
 110   bool HasCopyRequest() const {
 111     return !copy_requests_.empty();
 112   }
 113
 114   virtual void SetBackgroundColor(SkColor background_color);
 115   SkColor background_color() const { return background_color_; }
 116   // If contents_opaque(), return an opaque color else return a
 117   // non-opaque color.  Tries to return background_color(), if possible.
 118   SkColor SafeOpaqueBackgroundColor() const;
 119
 120   // A layer's bounds are in logical, non-page-scaled pixels (however, the
 121   // root layer's bounds are in physical pixels).
 122   void SetBounds(const gfx::Size& bounds);
 123   gfx::Size bounds() const { return bounds_; }
 124
 125   void SetMasksToBounds(bool masks_to_bounds);
 126   bool masks_to_bounds() const { return masks_to_bounds_; }
 127
 128   void SetMaskLayer(Layer* mask_layer);
 129   Layer* mask_layer() { return mask_layer_.get(); }
 130   const Layer* mask_layer() const { return mask_layer_.get(); }
 131
 132   virtual void SetNeedsDisplayRect(const gfx::Rect& dirty_rect);
 133   void SetNeedsDisplay() { SetNeedsDisplayRect(gfx::Rect(bounds())); }
 134
 135   void SetOpacity(float opacity);
 136   float opacity() const { return opacity_; }
 137   bool OpacityIsAnimating() const;
 138   virtual bool OpacityCanAnimateOnImplThread() const;
 139
 140   void SetBlendMode(SkXfermode::Mode blend_mode);
 141   SkXfermode::Mode blend_mode() const { return blend_mode_; }
 142
 143   bool uses_default_blend_mode() const {
 144     return blend_mode_ == SkXfermode::kSrcOver_Mode;
 145   }
 146
 147   // A layer is root for an isolated group when it and all its descendants are
 148   // drawn over a black and fully transparent background, creating an isolated
 149   // group. It should be used along with SetBlendMode(), in order to restrict
 150   // layers within the group to blend with layers outside this group.
 151   void SetIsRootForIsolatedGroup(bool root);
 152   bool is_root_for_isolated_group() const {
 153     return is_root_for_isolated_group_;
 154   }
 155
 156   void SetFilters(const FilterOperations& filters);
 157   const FilterOperations& filters() const { return filters_; }
 158   bool FilterIsAnimating() const;
 159
 160   // Background filters are filters applied to what is behind this layer, when
 161   // they are viewed through non-opaque regions in this layer. They are used
 162   // through the WebLayer interface, and are not exposed to HTML.
 163   void SetBackgroundFilters(const FilterOperations& filters);
 164   const FilterOperations& background_filters() const {
 165     return background_filters_;
 166   }
 167
 168   virtual void SetContentsOpaque(bool opaque);
 169   bool contents_opaque() const { return contents_opaque_; }
 170
 171   void SetPosition(const gfx::PointF& position);
 172   gfx::PointF position() const { return position_; }
 173
 174   void SetIsContainerForFixedPositionLayers(bool container);
 175   bool IsContainerForFixedPositionLayers() const;
 176
 177   void SetPositionConstraint(const LayerPositionConstraint& constraint);
 178   const LayerPositionConstraint& position_constraint() const {
 179     return position_constraint_;
 180   }
 181
 182   void SetTransform(const gfx::Transform& transform);
 183   const gfx::Transform& transform() const { return transform_; }
 184   bool TransformIsAnimating() const;
 185   bool AnimationsPreserveAxisAlignment() const;
 186   bool transform_is_invertible() const { return transform_is_invertible_; }
 187
 188   void SetTransformOrigin(const gfx::Point3F&);
 189   gfx::Point3F transform_origin() const { return transform_origin_; }
 190
 191   void SetScrollParent(Layer* parent);
 192
 193   Layer* scroll_parent() { return scroll_parent_; }
 194   const Layer* scroll_parent() const { return scroll_parent_; }
 195
 196   void AddScrollChild(Layer* child);
 197   void RemoveScrollChild(Layer* child);
 198
 199   std::set<Layer*>* scroll_children() { return scroll_children_.get(); }
 200   const std::set<Layer*>* scroll_children() const {
 201     return scroll_children_.get();
 202   }
 203
 204   void SetClipParent(Layer* ancestor);
 205
 206   Layer* clip_parent() { return clip_parent_; }
 207   const Layer* clip_parent() const {
 208     return clip_parent_;
 209   }
 210
 211   void AddClipChild(Layer* child);
 212   void RemoveClipChild(Layer* child);
 213
 214   std::set<Layer*>* clip_children() { return clip_children_.get(); }
 215   const std::set<Layer*>* clip_children() const {
 216     return clip_children_.get();
 217   }
 218
 219   DrawProperties<Layer>& draw_properties() { return draw_properties_; }
 220   const DrawProperties<Layer>& draw_properties() const {
 221     return draw_properties_;
 222   }
 223
 224   // The following are shortcut accessors to get various information from
 225   // draw_properties_
 226   const gfx::Transform& draw_transform() const {
 227     return draw_properties_.target_space_transform;
 228   }
 229   const gfx::Transform& screen_space_transform() const {
 230     return draw_properties_.screen_space_transform;
 231   }
 232   float draw_opacity() const { return draw_properties_.opacity; }
 233   bool draw_opacity_is_animating() const {
 234     return draw_properties_.opacity_is_animating;
 235   }
 236   bool draw_transform_is_animating() const {
 237     return draw_properties_.target_space_transform_is_animating;
 238   }
 239   bool screen_space_transform_is_animating() const {
 240     return draw_properties_.screen_space_transform_is_animating;
 241   }
 242   bool screen_space_opacity_is_animating() const {
 243     return draw_properties_.screen_space_opacity_is_animating;
 244   }
 245   bool is_clipped() const { return draw_properties_.is_clipped; }
 246   gfx::Rect clip_rect() const { return draw_properties_.clip_rect; }
 247   gfx::Rect drawable_content_rect() const {
 248     return draw_properties_.drawable_content_rect;
 249   }
 250   gfx::Rect visible_content_rect() const {
 251     return draw_properties_.visible_content_rect;
 252   }
 253   Layer* render_target() {
 254     DCHECK(!draw_properties_.render_target ||
 255            draw_properties_.render_target->render_surface());
 256     return draw_properties_.render_target;
 257   }
 258   const Layer* render_target() const {
 259     DCHECK(!draw_properties_.render_target ||
 260            draw_properties_.render_target->render_surface());
 261     return draw_properties_.render_target;
 262   }
 263   int num_unclipped_descendants() const {
 264     return draw_properties_.num_unclipped_descendants;
 265   }
 266
 267   RenderSurface* render_surface() const { return render_surface_.get(); }
 268   void SetScrollOffset(const gfx::ScrollOffset& scroll_offset);
 269   void SetScrollCompensationAdjustment(
 270       const gfx::Vector2dF& scroll_compensation_adjustment);
 271   gfx::Vector2dF ScrollCompensationAdjustment() const;
 272
 273   gfx::ScrollOffset scroll_offset() const { return scroll_offset_; }
 274   void SetScrollOffsetFromImplSide(const gfx::ScrollOffset& scroll_offset);
 275
 276   void SetScrollClipLayerId(int clip_layer_id);
 277   bool scrollable() const { return scroll_clip_layer_id_ != INVALID_ID; }
 278
 279   void SetUserScrollable(bool horizontal, bool vertical);
 280   bool user_scrollable_horizontal() const {
 281     return user_scrollable_horizontal_;
 282   }
 283   bool user_scrollable_vertical() const { return user_scrollable_vertical_; }
 284
 285   void SetShouldScrollOnMainThread(bool should_scroll_on_main_thread);
 286   bool should_scroll_on_main_thread() const {
 287     return should_scroll_on_main_thread_;
 288   }
 289
 290   void SetHaveWheelEventHandlers(bool have_wheel_event_handlers);
 291   bool have_wheel_event_handlers() const { return have_wheel_event_handlers_; }
 292
 293   void SetHaveScrollEventHandlers(bool have_scroll_event_handlers);
 294   bool have_scroll_event_handlers() const {
 295     return have_scroll_event_handlers_;
 296   }
 297
 298   void SetNonFastScrollableRegion(const Region& non_fast_scrollable_region);
 299   const Region& non_fast_scrollable_region() const {
 300     return non_fast_scrollable_region_;
 301   }
 302
 303   void SetTouchEventHandlerRegion(const Region& touch_event_handler_region);
 304   const Region& touch_event_handler_region() const {
 305     return touch_event_handler_region_;
 306   }
 307
 308   void SetScrollBlocksOn(ScrollBlocksOn scroll_blocks_on);
 309   ScrollBlocksOn scroll_blocks_on() const { return scroll_blocks_on_; }
 310
 311   void set_did_scroll_callback(const base::Closure& callback) {
 312     did_scroll_callback_ = callback;
 313   }
 314
 315   void SetDrawCheckerboardForMissingTiles(bool checkerboard);
 316   bool draw_checkerboard_for_missing_tiles() const {
 317     return draw_checkerboard_for_missing_tiles_;
 318   }
 319
 320   void SetForceRenderSurface(bool force_render_surface);
 321   bool force_render_surface() const { return force_render_surface_; }
 322
 323   gfx::Vector2dF ScrollDelta() const { return gfx::Vector2dF(); }
 324   gfx::ScrollOffset CurrentScrollOffset() const { return scroll_offset_; }
 325
 326   void SetDoubleSided(bool double_sided);
 327   bool double_sided() const { return double_sided_; }
 328
 329   void SetShouldFlattenTransform(bool flatten);
 330   bool should_flatten_transform() const { return should_flatten_transform_; }
 331
 332   bool Is3dSorted() const { return sorting_context_id_ != 0; }
 333
 334   void set_use_parent_backface_visibility(bool use) {
 335     use_parent_backface_visibility_ = use;
 336   }
 337   bool use_parent_backface_visibility() const {
 338     return use_parent_backface_visibility_;
 339   }
 340
 341   virtual void SetLayerTreeHost(LayerTreeHost* host);
 342
 343   virtual bool HasDelegatedContent() const;
 344   bool HasContributingDelegatedRenderPasses() const { return false; }
 345
 346   void SetIsDrawable(bool is_drawable);
 347
 348   void SetHideLayerAndSubtree(bool hide);
 349   bool hide_layer_and_subtree() const { return hide_layer_and_subtree_; }
 350
 351   void SetReplicaLayer(Layer* layer);
 352   Layer* replica_layer() { return replica_layer_.get(); }
 353   const Layer* replica_layer() const { return replica_layer_.get(); }
 354
 355   bool has_mask() const { return !!mask_layer_.get(); }
 356   bool has_replica() const { return !!replica_layer_.get(); }
 357   bool replica_has_mask() const {
 358     return replica_layer_.get() &&
 359            (mask_layer_.get() || replica_layer_->mask_layer_.get());
 360   }
 361
 362   int NumDescendantsThatDrawContent() const;
 363
 364   // This is only virtual for tests.
 365   // TODO(awoloszyn): Remove this once we no longer need it for tests
 366   virtual bool DrawsContent() const;
 367
 368   // This methods typically need to be overwritten by derived classes.
 369   virtual void SavePaintProperties();
 370   // Returns true iff any resources were updated that need to be committed.
 371   virtual bool Update(ResourceUpdateQueue* queue,
 372                       const OcclusionTracker<Layer>* occlusion);
 373   virtual bool NeedMoreUpdates();
 374   virtual void SetIsMask(bool is_mask) {}
 375   virtual void ReduceMemoryUsage() {}
 376   virtual void OnOutputSurfaceCreated() {}
 377   virtual bool IsSuitableForGpuRasterization() const;
 378
 379   virtual scoped_refptr<base::trace_event::ConvertableToTraceFormat>
 380   TakeDebugInfo();
 381
 382   void SetLayerClient(LayerClient* client) { client_ = client; }
 383
 384   virtual void PushPropertiesTo(LayerImpl* layer);
 385
 386   void CreateRenderSurface();
 387   void ClearRenderSurface();
 388
 389   void ClearRenderSurfaceLayerList();
 390
 391   // The contents scale converts from logical, non-page-scaled pixels to target
 392   // pixels. The contents scale is 1 for the root layer as it is already in
 393   // physical pixels. By default contents scale is forced to be 1 except for
 394   // subclasses of ContentsScalingLayer.
 395   float contents_scale_x() const { return draw_properties_.contents_scale_x; }
 396   float contents_scale_y() const { return draw_properties_.contents_scale_y; }
 397   gfx::Size content_bounds() const { return draw_properties_.content_bounds; }
 398
 399   virtual void CalculateContentsScale(float ideal_contents_scale,
 400                                       float* contents_scale_x,
 401                                       float* contents_scale_y,
 402                                       gfx::Size* content_bounds);
 403
 404   LayerTreeHost* layer_tree_host() { return layer_tree_host_; }
 405   const LayerTreeHost* layer_tree_host() const { return layer_tree_host_; }
 406
 407   // Set the priority of all desired textures in this layer.
 408   virtual void SetTexturePriorities(const PriorityCalculator& priority_calc) {}
 409
 410   bool AddAnimation(scoped_ptr<Animation> animation);
 411   void PauseAnimation(int animation_id, double time_offset);
 412   void RemoveAnimation(int animation_id);
 413   void RemoveAnimation(int animation_id, Animation::TargetProperty property);
 414
 415   LayerAnimationController* layer_animation_controller() {
 416     return layer_animation_controller_.get();
 417   }
 418   void SetLayerAnimationControllerForTest(
 419       scoped_refptr<LayerAnimationController> controller);
 420
 421   void set_layer_animation_delegate(AnimationDelegate* delegate) {
 422     layer_animation_controller_->set_layer_animation_delegate(delegate);
 423   }
 424
 425   bool HasActiveAnimation() const;
 426
 427   void AddLayerAnimationEventObserver(
 428       LayerAnimationEventObserver* animation_observer);
 429   void RemoveLayerAnimationEventObserver(
 430       LayerAnimationEventObserver* animation_observer);
 431
 432   virtual SimpleEnclosedRegion VisibleContentOpaqueRegion() const;
 433
 434   virtual ScrollbarLayerInterface* ToScrollbarLayer();
 435
 436   gfx::Rect LayerRectToContentRect(const gfx::Rect& layer_rect) const;
 437
 438   virtual skia::RefPtr<SkPicture> GetPicture() const;
 439
 440   // Constructs a LayerImpl of the correct runtime type for this Layer type.
 441   virtual scoped_ptr<LayerImpl> CreateLayerImpl(LayerTreeImpl* tree_impl);
 442
 443   bool NeedsDisplayForTesting() const { return !update_rect_.IsEmpty(); }
 444   void ResetNeedsDisplayForTesting() { update_rect_ = gfx::Rect(); }
 445
 446   RenderingStatsInstrumentation* rendering_stats_instrumentation() const;
 447
 448   const PaintProperties& paint_properties() const {
 449     return paint_properties_;
 450   }
 451
 452   // The scale at which contents should be rastered, to match the scale at
 453   // which they will drawn to the screen. This scale is a component of the
 454   // contents scale but does not include page/device scale factors.
 455   // TODO(danakj): This goes away when TiledLayer goes away.
 456   void set_raster_scale(float scale) { raster_scale_ = scale; }
 457   float raster_scale() const { return raster_scale_; }
 458   bool raster_scale_is_unknown() const { return raster_scale_ == 0.f; }
 459
 460   void SetNeedsPushProperties();
 461   bool needs_push_properties() const { return needs_push_properties_; }
 462   bool descendant_needs_push_properties() const {
 463     return num_dependents_need_push_properties_ > 0;
 464   }
 465   void reset_needs_push_properties_for_testing() {
 466     needs_push_properties_ = false;
 467   }
 468
 469   virtual void RunMicroBenchmark(MicroBenchmark* benchmark);
 470
 471   void Set3dSortingContextId(int id);
 472   int sorting_context_id() const { return sorting_context_id_; }
 473
 474   void set_transform_tree_index(int index) { transform_tree_index_ = index; }
 475   void set_clip_tree_index(int index) { clip_tree_index_ = index; }
 476   void set_opacity_tree_index(int index) { opacity_tree_index_ = index; }
 477   int clip_tree_index() const { return clip_tree_index_; }
 478   int transform_tree_index() const { return transform_tree_index_; }
 479   int opacity_tree_index() const { return opacity_tree_index_; }
 480
 481   void set_offset_to_transform_parent(gfx::Vector2dF offset) {
 482     offset_to_transform_parent_ = offset;
 483   }
 484   gfx::Vector2dF offset_to_transform_parent() const {
 485     return offset_to_transform_parent_;
 486   }
 487
 488   // TODO(vollick): Once we transition to transform and clip trees, rename these
 489   // functions and related values.  The "from property trees" functions below
 490   // use the transform and clip trees.  Eventually, we will use these functions
 491   // to compute the official values, but these functions are retained for
 492   // testing purposes until we've migrated.
 493
 494   const gfx::Rect& visible_rect_from_property_trees() const {
 495     return visible_rect_from_property_trees_;
 496   }
 497   void set_visible_rect_from_property_trees(const gfx::Rect& rect) {
 498     visible_rect_from_property_trees_ = rect;
 499   }
 500
 501   gfx::Transform screen_space_transform_from_property_trees(
 502       const TransformTree& tree) const;
 503   gfx::Transform draw_transform_from_property_trees(
 504       const TransformTree& tree) const;
 505   float DrawOpacityFromPropertyTrees(const OpacityTree& tree) const;
 506
 507   // TODO(vollick): These values are temporary and will be removed as soon as
 508   // render surface determinations are moved out of CDP. They only exist because
 509   // certain logic depends on whether or not a layer would render to a separate
 510   // surface, but CDP destroys surfaces and targets it doesn't need, so without
 511   // this boolean, this is impossible to determine after the fact without
 512   // wastefully recomputing it. This is public for the time being so that it can
 513   // be accessed from CDP.
 514   bool has_render_surface() const {
 515     return has_render_surface_;
 516   }
 517
 518   // Sets new frame timing requests for this layer.
 519   void SetFrameTimingRequests(const std::vector<FrameTimingRequest>& requests);
 520
 521  protected:
 522   friend class LayerImpl;
 523   friend class TreeSynchronizer;
 524   ~Layer() override;
 525
 526   Layer();
 527
 528   // These SetNeeds functions are in order of severity of update:
 529   //
 530   // Called when this layer has been modified in some way, but isn't sure
 531   // that it needs a commit yet.  It needs CalcDrawProperties and UpdateLayers
 532   // before it knows whether or not a commit is required.
 533   void SetNeedsUpdate();
 534   // Called when a property has been modified in a way that the layer
 535   // knows immediately that a commit is required.  This implies SetNeedsUpdate
 536   // as well as SetNeedsPushProperties to push that property.
 537   void SetNeedsCommit();
 538   // Called when there's been a change in layer structure.  Implies both
 539   // SetNeedsUpdate and SetNeedsCommit, but not SetNeedsPushProperties.
 540   void SetNeedsFullTreeSync();
 541
 542   // Called when the next commit should wait until the pending tree is activated
 543   // before finishing the commit and unblocking the main thread. Used to ensure
 544   // unused resources on the impl thread are returned before commit completes.
 545   void SetNextCommitWaitsForActivation();
 546
 547   // Will recalculate whether the layer draws content and set draws_content_
 548   // appropriately.
 549   void UpdateDrawsContent(bool has_drawable_content);
 550   virtual bool HasDrawableContent() const;
 551
 552   // Called when the layer's number of drawable descendants changes.
 553   void AddDrawableDescendants(int num);
 554
 555   void AddDependentNeedsPushProperties();
 556   void RemoveDependentNeedsPushProperties();
 557   bool parent_should_know_need_push_properties() const {
 558     return needs_push_properties() || descendant_needs_push_properties();
 559   }
 560
 561   bool IsPropertyChangeAllowed() const;
 562
 563   void reset_raster_scale_to_unknown() { raster_scale_ = 0.f; }
 564
 565   // This flag is set when the layer needs to push properties to the impl
 566   // side.
 567   bool needs_push_properties_;
 568
 569   // The number of direct children or dependent layers that need to be recursed
 570   // to in order for them or a descendent of them to push properties to the impl
 571   // side.
 572   int num_dependents_need_push_properties_;
 573
 574   // Tracks whether this layer may have changed stacking order with its
 575   // siblings.
 576   bool stacking_order_changed_;
 577
 578   // The update rect is the region of the compositor resource that was
 579   // actually updated by the compositor. For layers that may do updating
 580   // outside the compositor's control (i.e. plugin layers), this information
 581   // is not available and the update rect will remain empty.
 582   // Note this rect is in layer space (not content space).
 583   gfx::Rect update_rect_;
 584
 585   scoped_refptr<Layer> mask_layer_;
 586
 587   int layer_id_;
 588
 589   // When true, the layer is about to perform an update. Any commit requests
 590   // will be handled implicitly after the update completes.
 591   bool ignore_set_needs_commit_;
 592
 593   // Layers that share a sorting context id will be sorted together in 3d
 594   // space.  0 is a special value that means this layer will not be sorted and
 595   // will be drawn in paint order.
 596   int sorting_context_id_;
 597
 598  private:
 599   friend class base::RefCounted<Layer>;
 600   friend class LayerTreeHostCommon;
 601   void SetParent(Layer* layer);
 602   bool DescendantIsFixedToContainerLayer() const;
 603
 604   // This should only be called during BeginMainFrame since it does not
 605   // trigger a Commit.
 606   void SetHasRenderSurface(bool has_render_surface);
 607
 608   // Returns the index of the child or -1 if not found.
 609   int IndexOfChild(const Layer* reference);
 610
 611   // This should only be called from RemoveFromParent().
 612   void RemoveChildOrDependent(Layer* child);
 613
 614   // LayerAnimationValueProvider implementation.
 615   gfx::ScrollOffset ScrollOffsetForAnimation() const override;
 616
 617   // LayerAnimationValueObserver implementation.
 618   void OnFilterAnimated(const FilterOperations& filters) override;
 619   void OnOpacityAnimated(float opacity) override;
 620   void OnTransformAnimated(const gfx::Transform& transform) override;
 621   void OnScrollOffsetAnimated(const gfx::ScrollOffset& scroll_offset) override;
 622   void OnAnimationWaitingForDeletion() override;
 623   bool IsActive() const override;
 624
 625   // If this layer has a scroll parent, it removes |this| from its list of
 626   // scroll children.
 627   void RemoveFromScrollTree();
 628
 629   // If this layer has a clip parent, it removes |this| from its list of clip
 630   // children.
 631   void RemoveFromClipTree();
 632
 633   LayerList children_;
 634   Layer* parent_;
 635
 636   // Layer instances have a weak pointer to their LayerTreeHost.
 637   // This pointer value is nil when a Layer is not in a tree and is
 638   // updated via SetLayerTreeHost() if a layer moves between trees.
 639   LayerTreeHost* layer_tree_host_;
 640
 641   scoped_refptr<LayerAnimationController> layer_animation_controller_;
 642
 643   // Layer properties.
 644   gfx::Size bounds_;
 645
 646   gfx::ScrollOffset scroll_offset_;
 647   gfx::Vector2dF scroll_compensation_adjustment_;
 648   // This variable indicates which ancestor layer (if any) whose size,
 649   // transformed relative to this layer, defines the maximum scroll offset for
 650   // this layer.
 651   int scroll_clip_layer_id_;
 652   int num_descendants_that_draw_content_;
 653   int transform_tree_index_;
 654   int opacity_tree_index_;
 655   int clip_tree_index_;
 656   gfx::Vector2dF offset_to_transform_parent_;
 657   bool should_scroll_on_main_thread_ : 1;
 658   bool have_wheel_event_handlers_ : 1;
 659   bool have_scroll_event_handlers_ : 1;
 660   bool user_scrollable_horizontal_ : 1;
 661   bool user_scrollable_vertical_ : 1;
 662   bool is_root_for_isolated_group_ : 1;
 663   bool is_container_for_fixed_position_layers_ : 1;
 664   bool is_drawable_ : 1;
 665   bool draws_content_ : 1;
 666   bool hide_layer_and_subtree_ : 1;
 667   bool masks_to_bounds_ : 1;
 668   bool contents_opaque_ : 1;
 669   bool double_sided_ : 1;
 670   bool should_flatten_transform_ : 1;
 671   bool use_parent_backface_visibility_ : 1;
 672   bool draw_checkerboard_for_missing_tiles_ : 1;
 673   bool force_render_surface_ : 1;
 674   bool transform_is_invertible_ : 1;
 675   bool has_render_surface_ : 1;
 676   ScrollBlocksOn scroll_blocks_on_ : 3;
 677   Region non_fast_scrollable_region_;
 678   Region touch_event_handler_region_;
 679   gfx::PointF position_;
 680   SkColor background_color_;
 681   float opacity_;
 682   SkXfermode::Mode blend_mode_;
 683   FilterOperations filters_;
 684   FilterOperations background_filters_;
 685   LayerPositionConstraint position_constraint_;
 686   Layer* scroll_parent_;
 687   scoped_ptr<std::set<Layer*>> scroll_children_;
 688
 689   Layer* clip_parent_;
 690   scoped_ptr<std::set<Layer*>> clip_children_;
 691
 692   gfx::Transform transform_;
 693   gfx::Point3F transform_origin_;
 694
 695   // Replica layer used for reflections.
 696   scoped_refptr<Layer> replica_layer_;
 697
 698   // Transient properties.
 699   float raster_scale_;
 700
 701   LayerClient* client_;
 702
 703   ScopedPtrVector<CopyOutputRequest> copy_requests_;
 704
 705   base::Closure did_scroll_callback_;
 706
 707   DrawProperties<Layer> draw_properties_;
 708
 709   PaintProperties paint_properties_;
 710   // TODO(awoloszyn): This is redundant with has_render_surface_,
 711   // and should get removed once it is no longer needed on main thread.
 712   scoped_ptr<RenderSurface> render_surface_;
 713
 714   gfx::Rect visible_rect_from_property_trees_;
 715
 716   std::vector<FrameTimingRequest> frame_timing_requests_;
 717   bool frame_timing_requests_dirty_;
 718
 719   DISALLOW_COPY_AND_ASSIGN(Layer);
 720 };
 721
 722 }  // namespace cc
 723
 724 #endif  // CC_LAYERS_LAYER_H_