Avoid compositing updates after style recalcs which have no compositing implications
[WebKit-https.git] / Source / WebCore / rendering / RenderLayerCompositor.h
1 /*
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11  *    documentation and/or other materials provided with the distribution.
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25
26 #ifndef RenderLayerCompositor_h
27 #define RenderLayerCompositor_h
28
29 #include "ChromeClient.h"
30 #include "GraphicsLayerClient.h"
31 #include "GraphicsLayerUpdater.h"
32 #include "RenderLayer.h"
33 #include <wtf/HashMap.h>
34
35 namespace WebCore {
36
37 class FixedPositionViewportConstraints;
38 class GraphicsLayer;
39 class GraphicsLayerUpdater;
40 class RenderEmbeddedObject;
41 class RenderNamedFlowFragment;
42 class RenderVideo;
43 class RenderWidget;
44 class ScrollingCoordinator;
45 class StickyPositionViewportConstraints;
46 class TiledBacking;
47
48 typedef unsigned LayerTreeFlags;
49
50 enum CompositingUpdateType {
51     CompositingUpdateAfterStyleChange,
52     CompositingUpdateAfterLayout,
53     CompositingUpdateOnHitTest,
54     CompositingUpdateOnScroll,
55     CompositingUpdateOnCompositedScroll
56 };
57
58 enum {
59     CompositingReasonNone                                   = 0,
60     CompositingReason3DTransform                            = 1 << 0,
61     CompositingReasonVideo                                  = 1 << 1,
62     CompositingReasonCanvas                                 = 1 << 2,
63     CompositingReasonPlugin                                 = 1 << 3,
64     CompositingReasonIFrame                                 = 1 << 4,
65     CompositingReasonBackfaceVisibilityHidden               = 1 << 5,
66     CompositingReasonClipsCompositingDescendants            = 1 << 6,
67     CompositingReasonAnimation                              = 1 << 7,
68     CompositingReasonFilters                                = 1 << 8,
69     CompositingReasonPositionFixed                          = 1 << 9,
70     CompositingReasonPositionSticky                         = 1 << 10,
71     CompositingReasonOverflowScrollingTouch                 = 1 << 11,
72     CompositingReasonStacking                               = 1 << 12,
73     CompositingReasonOverlap                                = 1 << 13,
74     CompositingReasonNegativeZIndexChildren                 = 1 << 14,
75     CompositingReasonTransformWithCompositedDescendants     = 1 << 15,
76     CompositingReasonOpacityWithCompositedDescendants       = 1 << 16,
77     CompositingReasonMaskWithCompositedDescendants          = 1 << 17,
78     CompositingReasonReflectionWithCompositedDescendants    = 1 << 18,
79     CompositingReasonFilterWithCompositedDescendants        = 1 << 19,
80     CompositingReasonBlendingWithCompositedDescendants      = 1 << 20,
81     CompositingReasonPerspective                            = 1 << 21,
82     CompositingReasonPreserve3D                             = 1 << 22,
83     CompositingReasonRoot                                   = 1 << 23,
84     CompositingReasonIsolatesCompositedBlendingDescendants  = 1 << 24,
85 };
86 typedef unsigned CompositingReasons;
87
88 // RenderLayerCompositor manages the hierarchy of
89 // composited RenderLayers. It determines which RenderLayers
90 // become compositing, and creates and maintains a hierarchy of
91 // GraphicsLayers based on the RenderLayer painting order.
92 // 
93 // There is one RenderLayerCompositor per RenderView.
94
95 class RenderLayerCompositor final : public GraphicsLayerClient, public GraphicsLayerUpdaterClient {
96     WTF_MAKE_FAST_ALLOCATED;
97 public:
98     explicit RenderLayerCompositor(RenderView&);
99     virtual ~RenderLayerCompositor();
100
101     // Return true if this RenderView is in "compositing mode" (i.e. has one or more
102     // composited RenderLayers)
103     bool inCompositingMode() const { return m_compositing; }
104     // This will make a compositing layer at the root automatically, and hook up to
105     // the native view/window system.
106     void enableCompositingMode(bool enable = true);
107
108     bool inForcedCompositingMode() const { return m_forceCompositingMode; }
109
110     // Returns true if the accelerated compositing is enabled
111     bool hasAcceleratedCompositing() const { return m_hasAcceleratedCompositing; }
112
113     bool canRender3DTransforms() const;
114
115     // Copy the accelerated compositing related flags from Settings
116     void cacheAcceleratedCompositingFlags();
117
118     // Called when the layer hierarchy needs to be updated (compositing layers have been
119     // created, destroyed or re-parented).
120     void setCompositingLayersNeedRebuild(bool needRebuild = true);
121     bool compositingLayersNeedRebuild() const { return m_compositingLayersNeedRebuild; }
122     
123     void willRecalcStyle();
124     void didRecalcStyleWithNoPendingLayout();
125
126     // GraphicsLayers buffer state, which gets pushed to the underlying platform layers
127     // at specific times.
128     void scheduleLayerFlush(bool canThrottle);
129     void flushPendingLayerChanges(bool isFlushRoot = true);
130     
131     // flushPendingLayerChanges() flushes the entire GraphicsLayer tree, which can cross frame boundaries.
132     // This call returns the rootmost compositor that is being flushed (including self).
133     RenderLayerCompositor* enclosingCompositorFlushingLayers() const;
134
135     // Called when the GraphicsLayer for the given RenderLayer has flushed changes inside of flushPendingLayerChanges().
136     void didFlushChangesForLayer(RenderLayer&, const GraphicsLayer*);
137
138     // Called when something outside WebKit affects the visible rect (e.g. delegated scrolling). Might schedule a layer flush.
139     void didChangeVisibleRect();
140     
141     // Rebuild the tree of compositing layers
142     void updateCompositingLayers(CompositingUpdateType, RenderLayer* updateRoot = nullptr);
143     // This is only used when state changes and we do not exepect a style update or layout to happen soon (e.g. when
144     // we discover that an iframe is overlapped during painting).
145     void scheduleCompositingLayerUpdate();
146     // This is used to cancel any pending update timers when the document goes into page cache.
147     void cancelCompositingLayerUpdate();
148
149     // Update the compositing state of the given layer. Returns true if that state changed.
150     enum CompositingChangeRepaint { CompositingChangeRepaintNow, CompositingChangeWillRepaintLater };
151     bool updateLayerCompositingState(RenderLayer&, CompositingChangeRepaint = CompositingChangeRepaintNow);
152
153     // Update the geometry for compositing children of compositingAncestor.
154     void updateCompositingDescendantGeometry(RenderLayer& compositingAncestor, RenderLayer&, bool compositedChildrenOnly);
155     
156     // Whether layer's backing needs a graphics layer to do clipping by an ancestor (non-stacking-context parent with overflow).
157     bool clippedByAncestor(RenderLayer&) const;
158     // Whether layer's backing needs a graphics layer to clip z-order children of the given layer.
159     bool clipsCompositingDescendants(const RenderLayer&) const;
160
161     // Whether the given layer needs an extra 'contents' layer.
162     bool needsContentsCompositingLayer(const RenderLayer&) const;
163
164     bool supportsFixedRootBackgroundCompositing() const;
165     bool needsFixedRootBackgroundLayer(const RenderLayer&) const;
166     GraphicsLayer* fixedRootBackgroundLayer() const;
167     
168     // Repaint the appropriate layers when the given RenderLayer starts or stops being composited.
169     void repaintOnCompositingChange(RenderLayer&);
170     
171     void repaintInCompositedAncestor(RenderLayer&, const LayoutRect&);
172     
173     // Notify us that a layer has been added or removed
174     void layerWasAdded(RenderLayer& parent, RenderLayer& child);
175     void layerWillBeRemoved(RenderLayer& parent, RenderLayer& child);
176
177     void layerStyleChanged(StyleDifference, RenderLayer&, const RenderStyle* oldStyle);
178
179     static bool canCompositeClipPath(const RenderLayer&);
180
181     // Get the nearest ancestor layer that has overflow or clip, but is not a stacking context
182     RenderLayer* enclosingNonStackingClippingLayer(const RenderLayer&) const;
183
184     // Repaint all composited layers.
185     void repaintCompositedLayers();
186
187     // Returns true if the given layer needs it own backing store.
188     bool requiresOwnBackingStore(const RenderLayer&, const RenderLayer* compositingAncestorLayer, const LayoutRect& layerCompositedBoundsInAncestor, const LayoutRect& ancestorCompositedBounds) const;
189
190     WEBCORE_EXPORT RenderLayer& rootRenderLayer() const;
191     GraphicsLayer* rootGraphicsLayer() const;
192     WEBCORE_EXPORT GraphicsLayer* scrollLayer() const;
193     GraphicsLayer* clipLayer() const;
194     GraphicsLayer* rootContentLayer() const;
195
196 #if ENABLE(RUBBER_BANDING)
197     GraphicsLayer* headerLayer() const;
198     GraphicsLayer* footerLayer() const;
199 #endif
200
201     enum RootLayerAttachment {
202         RootLayerUnattached,
203         RootLayerAttachedViaChromeClient,
204         RootLayerAttachedViaEnclosingFrame
205     };
206
207     RootLayerAttachment rootLayerAttachment() const { return m_rootLayerAttachment; }
208     void updateRootLayerAttachment();
209     void updateRootLayerPosition();
210     
211     void setIsInWindow(bool);
212
213     void clearBackingForAllLayers();
214     
215     void layerBecameComposited(const RenderLayer&) { ++m_compositedLayerCount; }
216     void layerBecameNonComposited(const RenderLayer&);
217     
218 #if ENABLE(VIDEO)
219     // Use by RenderVideo to ask if it should try to use accelerated compositing.
220     bool canAccelerateVideoRendering(RenderVideo&) const;
221 #endif
222
223     // Walk the tree looking for layers with 3d transforms. Useful in case you need
224     // to know if there is non-affine content, e.g. for drawing into an image.
225     bool has3DContent() const;
226     
227     // Most platforms connect compositing layer trees between iframes and their parent document.
228     // Some (currently just Mac) allow iframes to do their own compositing.
229     static bool allowsIndependentlyCompositedFrames(const FrameView*);
230     bool shouldPropagateCompositingToEnclosingFrame() const;
231
232     static RenderLayerCompositor* frameContentsCompositor(RenderWidget*);
233     // Return true if the layers changed.
234     static bool parentFrameContentLayers(RenderWidget*);
235
236     // Update the geometry of the layers used for clipping and scrolling in frames.
237     void frameViewDidChangeLocation(const IntPoint& contentsOffset);
238     void frameViewDidChangeSize();
239     void frameViewDidScroll();
240     void frameViewDidAddOrRemoveScrollbars();
241     void frameViewDidLayout();
242     void rootFixedBackgroundsChanged();
243
244     void scrollingLayerDidChange(RenderLayer&);
245     void fixedRootBackgroundLayerChanged();
246
247     String layerTreeAsText(LayerTreeFlags);
248
249     virtual float deviceScaleFactor() const override;
250     virtual float contentsScaleMultiplierForNewTiles(const GraphicsLayer*) const override;
251     virtual float pageScaleFactor() const override;
252     virtual float zoomedOutPageScaleFactor() const override;
253
254     virtual void didCommitChangesForLayer(const GraphicsLayer*) const override;
255     virtual void notifyFlushBeforeDisplayRefresh(const GraphicsLayer*) override;
256
257     void layerTiledBackingUsageChanged(const GraphicsLayer*, bool /*usingTiledBacking*/);
258     
259     bool acceleratedDrawingEnabled() const { return m_acceleratedDrawingEnabled; }
260
261     void deviceOrPageScaleFactorChanged();
262
263     void windowScreenDidChange(PlatformDisplayID);
264
265     GraphicsLayer* layerForHorizontalScrollbar() const { return m_layerForHorizontalScrollbar.get(); }
266     GraphicsLayer* layerForVerticalScrollbar() const { return m_layerForVerticalScrollbar.get(); }
267     GraphicsLayer* layerForScrollCorner() const { return m_layerForScrollCorner.get(); }
268 #if ENABLE(RUBBER_BANDING)
269     GraphicsLayer* layerForOverhangAreas() const { return m_layerForOverhangAreas.get(); }
270     GraphicsLayer* layerForContentShadow() const { return m_contentShadowLayer.get(); }
271
272     GraphicsLayer* updateLayerForTopOverhangArea(bool wantsLayer);
273     GraphicsLayer* updateLayerForBottomOverhangArea(bool wantsLayer);
274     GraphicsLayer* updateLayerForHeader(bool wantsLayer);
275     GraphicsLayer* updateLayerForFooter(bool wantsLayer);
276 #endif
277
278     ScrollableArea* scrollableAreaForScrollLayerID(ScrollingNodeID) const;
279
280     void updateScrollCoordinatedStatus(RenderLayer&);
281     void removeFromScrollCoordinatedLayers(RenderLayer&);
282
283     void willRemoveScrollingLayerWithBacking(RenderLayer&, RenderLayerBacking&);
284     void didAddScrollingLayer(RenderLayer&);
285
286 #if PLATFORM(IOS)
287     void registerAllViewportConstrainedLayers();
288     void unregisterAllViewportConstrainedLayers();
289
290     void registerAllScrollingLayers();
291     void unregisterAllScrollingLayers();
292 #endif
293
294     void resetTrackedRepaintRects();
295     void setTracksRepaints(bool);
296
297     void setShouldReevaluateCompositingAfterLayout() { m_reevaluateCompositingAfterLayout = true; }
298
299     bool viewHasTransparentBackground(Color* backgroundColor = nullptr) const;
300
301     bool hasNonMainLayersWithTiledBacking() const { return m_layersWithTiledBackingCount; }
302
303     CompositingReasons reasonsForCompositing(const RenderLayer&) const;
304
305     void setLayerFlushThrottlingEnabled(bool);
306     void disableLayerFlushThrottlingTemporarilyForInteraction();
307     
308     void didPaintBacking(RenderLayerBacking*);
309
310     void setRootExtendedBackgroundColor(const Color&);
311     Color rootExtendedBackgroundColor() const { return m_rootExtendedBackgroundColor; }
312
313     // For testing.
314     WEBCORE_EXPORT void startTrackingLayerFlushes();
315     WEBCORE_EXPORT unsigned layerFlushCount() const;
316
317     WEBCORE_EXPORT void startTrackingCompositingUpdates();
318     WEBCORE_EXPORT unsigned compositingUpdateCount() const;
319
320 private:
321     class OverlapMap;
322     struct CompositingState;
323     struct OverlapExtent;
324
325     // GraphicsLayerClient implementation
326     virtual void notifyFlushRequired(const GraphicsLayer*) override;
327     virtual void paintContents(const GraphicsLayer*, GraphicsContext&, GraphicsLayerPaintingPhase, const FloatRect&) override;
328     virtual void customPositionForVisibleRectComputation(const GraphicsLayer*, FloatPoint&) const override;
329     virtual bool isTrackingRepaints() const override;
330     
331     // GraphicsLayerUpdaterClient implementation
332     virtual void flushLayersSoon(GraphicsLayerUpdater&) override;
333
334     // Whether the given RL needs a compositing layer.
335     bool needsToBeComposited(const RenderLayer&, RenderLayer::ViewportConstrainedNotCompositedReason* = nullptr) const;
336     // Whether the layer has an intrinsic need for compositing layer.
337     bool requiresCompositingLayer(const RenderLayer&, RenderLayer::ViewportConstrainedNotCompositedReason* = nullptr) const;
338     // Whether the layer could ever be composited.
339     bool canBeComposited(const RenderLayer&) const;
340
341     // Make or destroy the backing for this layer; returns true if backing changed.
342     enum class BackingRequired { No, Yes, Unknown };
343     bool updateBacking(RenderLayer&, CompositingChangeRepaint shouldRepaint, BackingRequired = BackingRequired::Unknown);
344
345     void clearBackingForLayerIncludingDescendants(RenderLayer&);
346     void setIsInWindowForLayerIncludingDescendants(RenderLayer&, bool isInWindow);
347
348     // Repaint this and its child layers.
349     void recursiveRepaintLayer(RenderLayer&);
350
351     void computeExtent(const OverlapMap&, const RenderLayer&, OverlapExtent&) const;
352     void addToOverlapMap(OverlapMap&, const RenderLayer&, OverlapExtent&);
353     void addToOverlapMapRecursive(OverlapMap&, const RenderLayer&, const RenderLayer* ancestorLayer = nullptr);
354
355     void updateCompositingLayersTimerFired();
356
357     // Returns true if any layer's compositing changed
358     void computeCompositingRequirements(RenderLayer* ancestorLayer, RenderLayer&, OverlapMap&, CompositingState&, bool& layersChanged, bool& descendantHas3DTransform);
359
360     void computeRegionCompositingRequirements(RenderNamedFlowFragment*, OverlapMap&, CompositingState&, bool& layersChanged, bool& anyDescendantHas3DTransform);
361
362     void computeCompositingRequirementsForNamedFlowFixed(RenderLayer&, OverlapMap&, CompositingState&, bool& layersChanged, bool& anyDescendantHas3DTransform);
363
364     // Recurses down the tree, parenting descendant compositing layers and collecting an array of child layers for the current compositing layer.
365     void rebuildCompositingLayerTree(RenderLayer&, Vector<GraphicsLayer*>& childGraphicsLayersOfEnclosingLayer, int depth);
366
367     // Recurses down the RenderFlowThread tree, parenting descendant compositing layers and collecting an array of child 
368     // layers for the current compositing layer corresponding to the anonymous region (that belongs to the region's parent).
369     void rebuildRegionCompositingLayerTree(RenderNamedFlowFragment*, Vector<GraphicsLayer*>& childList, int depth);
370
371     void rebuildCompositingLayerTreeForNamedFlowFixed(RenderLayer&, Vector<GraphicsLayer*>& childList, int depth);
372
373     // Recurses down the tree, updating layer geometry only.
374     void updateLayerTreeGeometry(RenderLayer&, int depth);
375     
376     // Hook compositing layers together
377     void setCompositingParent(RenderLayer& childLayer, RenderLayer* parentLayer);
378     void removeCompositedChildren(RenderLayer&);
379
380     bool layerHas3DContent(const RenderLayer&) const;
381     bool isRunningTransformAnimation(RenderLayerModelObject&) const;
382
383     void appendDocumentOverlayLayers(Vector<GraphicsLayer*>&);
384     bool hasAnyAdditionalCompositedLayers(const RenderLayer& rootLayer) const;
385
386     void ensureRootLayer();
387     void destroyRootLayer();
388
389     void attachRootLayer(RootLayerAttachment);
390     void detachRootLayer();
391     
392     void rootLayerAttachmentChanged();
393
394     void updateOverflowControlsLayers();
395
396     void updateScrollLayerPosition();
397
398     FloatPoint positionForClipLayer() const;
399
400     void notifyIFramesOfCompositingChange();
401
402     bool isFlushingLayers() const { return m_flushingLayers; }
403     void updateScrollCoordinatedLayersAfterFlushIncludingSubframes();
404     void updateScrollCoordinatedLayersAfterFlush();
405     
406     Page* page() const;
407     
408     GraphicsLayerFactory* graphicsLayerFactory() const;
409     ScrollingCoordinator* scrollingCoordinator() const;
410
411 #if USE(REQUEST_ANIMATION_FRAME_DISPLAY_MONITOR)
412     RefPtr<DisplayRefreshMonitor> createDisplayRefreshMonitor(PlatformDisplayID) const override;
413 #endif
414
415     bool requiresCompositingForAnimation(RenderLayerModelObject&) const;
416     bool requiresCompositingForTransform(RenderLayerModelObject&) const;
417     bool requiresCompositingForBackfaceVisibility(RenderLayerModelObject&) const;
418     bool requiresCompositingForVideo(RenderLayerModelObject&) const;
419     bool requiresCompositingForCanvas(RenderLayerModelObject&) const;
420     bool requiresCompositingForPlugin(RenderLayerModelObject&) const;
421     bool requiresCompositingForFrame(RenderLayerModelObject&) const;
422     bool requiresCompositingForFilters(RenderLayerModelObject&) const;
423     bool requiresCompositingForScrollableFrame() const;
424     bool requiresCompositingForPosition(RenderLayerModelObject&, const RenderLayer&, RenderLayer::ViewportConstrainedNotCompositedReason* = nullptr) const;
425     bool requiresCompositingForOverflowScrolling(const RenderLayer&) const;
426     bool requiresCompositingForIndirectReason(RenderLayerModelObject&, bool hasCompositedDescendants, bool has3DTransformedDescendants, RenderLayer::IndirectCompositingReason&) const;
427
428 #if PLATFORM(IOS)
429     bool requiresCompositingForScrolling(const RenderLayer&) const;
430
431     void updateCustomLayersAfterFlush();
432
433     ChromeClient* chromeClient() const;
434
435 #endif
436
437     void updateScrollCoordinationForThisFrame(ScrollingNodeID);
438     ScrollingNodeID attachScrollingNode(RenderLayer&, ScrollingNodeType, ScrollingNodeID parentNodeID);
439     void updateScrollCoordinatedLayer(RenderLayer&, LayerScrollCoordinationRoles);
440     void detachScrollCoordinatedLayer(RenderLayer&, LayerScrollCoordinationRoles);
441     void reattachSubframeScrollLayers();
442     
443     FixedPositionViewportConstraints computeFixedViewportConstraints(RenderLayer&) const;
444     StickyPositionViewportConstraints computeStickyViewportConstraints(RenderLayer&) const;
445
446     bool requiresScrollLayer(RootLayerAttachment) const;
447     bool requiresHorizontalScrollbarLayer() const;
448     bool requiresVerticalScrollbarLayer() const;
449     bool requiresScrollCornerLayer() const;
450 #if ENABLE(RUBBER_BANDING)
451     bool requiresOverhangAreasLayer() const;
452     bool requiresContentShadowLayer() const;
453 #endif
454
455     // True if the FrameView uses a ScrollingCoordinator.
456     bool hasCoordinatedScrolling() const;
457
458     bool isAsyncScrollableStickyLayer(const RenderLayer&, const RenderLayer** enclosingAcceleratedOverflowLayer = nullptr) const;
459     bool isViewportConstrainedFixedOrStickyLayer(const RenderLayer&) const;
460     
461     bool shouldCompositeOverflowControls() const;
462
463     void scheduleLayerFlushNow();
464     bool isThrottlingLayerFlushes() const;
465     void startInitialLayerFlushTimerIfNeeded();
466     void startLayerFlushTimerIfNeeded();
467     void layerFlushTimerFired();
468
469     void paintRelatedMilestonesTimerFired();
470
471 #if !LOG_DISABLED
472     const char* logReasonsForCompositing(const RenderLayer&);
473     void logLayerInfo(const RenderLayer&, int depth);
474 #endif
475
476     bool mainFrameBackingIsTiled() const;
477
478 private:
479     RenderView& m_renderView;
480     std::unique_ptr<GraphicsLayer> m_rootContentLayer;
481     Timer m_updateCompositingLayersTimer;
482
483     bool m_hasAcceleratedCompositing;
484     ChromeClient::CompositingTriggerFlags m_compositingTriggers;
485
486     bool m_showDebugBorders;
487     bool m_showRepaintCounter;
488     bool m_acceleratedDrawingEnabled;
489
490     // When true, we have to wait until layout has happened before we can decide whether to enter compositing mode,
491     // because only then do we know the final size of plugins and iframes.
492     mutable bool m_reevaluateCompositingAfterLayout;
493
494     bool m_compositing;
495     bool m_compositingLayersNeedRebuild;
496     bool m_flushingLayers;
497     bool m_shouldFlushOnReattach;
498     bool m_forceCompositingMode;
499     bool m_inPostLayoutUpdate; // true when it's OK to trust layout information (e.g. layer sizes and positions)
500     bool m_subframeScrollLayersNeedReattach;
501
502     bool m_isTrackingRepaints; // Used for testing.
503
504     int m_compositedLayerCount { 0 };
505     unsigned m_layersWithTiledBackingCount { 0 };
506     unsigned m_layerFlushCount { 0 };
507     unsigned m_compositingUpdateCount { 0 };
508
509     RootLayerAttachment m_rootLayerAttachment;
510
511     // Enclosing clipping layer for iframe content
512     std::unique_ptr<GraphicsLayer> m_clipLayer;
513     std::unique_ptr<GraphicsLayer> m_scrollLayer;
514
515 #if PLATFORM(IOS)
516     HashSet<RenderLayer*> m_scrollingLayers;
517     HashSet<RenderLayer*> m_scrollingLayersNeedingUpdate;
518 #endif
519     HashSet<RenderLayer*> m_scrollCoordinatedLayers;
520     HashSet<RenderLayer*> m_scrollCoordinatedLayersNeedingUpdate;
521
522     // Enclosing layer for overflow controls and the clipping layer
523     std::unique_ptr<GraphicsLayer> m_overflowControlsHostLayer;
524
525     // Layers for overflow controls
526     std::unique_ptr<GraphicsLayer> m_layerForHorizontalScrollbar;
527     std::unique_ptr<GraphicsLayer> m_layerForVerticalScrollbar;
528     std::unique_ptr<GraphicsLayer> m_layerForScrollCorner;
529 #if ENABLE(RUBBER_BANDING)
530     std::unique_ptr<GraphicsLayer> m_layerForOverhangAreas;
531     std::unique_ptr<GraphicsLayer> m_contentShadowLayer;
532     std::unique_ptr<GraphicsLayer> m_layerForTopOverhangArea;
533     std::unique_ptr<GraphicsLayer> m_layerForBottomOverhangArea;
534     std::unique_ptr<GraphicsLayer> m_layerForHeader;
535     std::unique_ptr<GraphicsLayer> m_layerForFooter;
536 #endif
537
538     std::unique_ptr<GraphicsLayerUpdater> m_layerUpdater; // Updates tiled layer visible area periodically while animations are running.
539
540     Timer m_layerFlushTimer;
541     bool m_layerFlushThrottlingEnabled;
542     bool m_layerFlushThrottlingTemporarilyDisabledForInteraction;
543     bool m_hasPendingLayerFlush;
544     bool m_layerNeedsCompositingUpdate { false };
545
546     Timer m_paintRelatedMilestonesTimer;
547
548 #if !LOG_DISABLED
549     int m_rootLayerUpdateCount { 0 };
550     int m_obligateCompositedLayerCount { 0 }; // count of layer that have to be composited.
551     int m_secondaryCompositedLayerCount { 0 }; // count of layers that have to be composited because of stacking or overlap.
552     double m_obligatoryBackingStoreBytes { 0 };
553     double m_secondaryBackingStoreBytes { 0 };
554 #endif
555
556     Color m_rootExtendedBackgroundColor;
557
558     HashMap<ScrollingNodeID, RenderLayer*> m_scrollingNodeToLayerMap;
559 };
560
561
562 } // namespace WebCore
563
564 #endif // RenderLayerCompositor_h