Work towards having frames in the scrolling tree
[WebKit-https.git] / Source / WebCore / rendering / RenderLayerCompositor.h
1 /*
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3  *
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5  * modification, are permitted provided that the following conditions
6  * are met:
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8  *    notice, this list of conditions and the following disclaimer.
9  * 2. Redistributions in binary form must reproduce the above copyright
10  *    notice, this list of conditions and the following disclaimer in the
11  *    documentation and/or other materials provided with the distribution.
12  *
13  * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
14  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
17  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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24  */
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 : public GraphicsLayerClient, public GraphicsLayerUpdaterClient {
96     WTF_MAKE_FAST_ALLOCATED;
97 public:
98     explicit RenderLayerCompositor(RenderView&);
99     ~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     // GraphicsLayers buffer state, which gets pushed to the underlying platform layers
124     // at specific times.
125     void scheduleLayerFlush(bool canThrottle);
126     void flushPendingLayerChanges(bool isFlushRoot = true);
127     
128     // flushPendingLayerChanges() flushes the entire GraphicsLayer tree, which can cross frame boundaries.
129     // This call returns the rootmost compositor that is being flushed (including self).
130     RenderLayerCompositor* enclosingCompositorFlushingLayers() const;
131
132     // Called when the GraphicsLayer for the given RenderLayer has flushed changes inside of flushPendingLayerChanges().
133     void didFlushChangesForLayer(RenderLayer&, const GraphicsLayer*);
134
135     // Called when something outside WebKit affects the visible rect (e.g. delegated scrolling). Might schedule a layer flush.
136     void didChangeVisibleRect();
137     
138     // Rebuild the tree of compositing layers
139     void updateCompositingLayers(CompositingUpdateType, RenderLayer* updateRoot = nullptr);
140     // This is only used when state changes and we do not exepect a style update or layout to happen soon (e.g. when
141     // we discover that an iframe is overlapped during painting).
142     void scheduleCompositingLayerUpdate();
143
144     // Update the compositing state of the given layer. Returns true if that state changed.
145     enum CompositingChangeRepaint { CompositingChangeRepaintNow, CompositingChangeWillRepaintLater };
146     bool updateLayerCompositingState(RenderLayer&, CompositingChangeRepaint = CompositingChangeRepaintNow);
147
148     // Update the geometry for compositing children of compositingAncestor.
149     void updateCompositingDescendantGeometry(RenderLayer& compositingAncestor, RenderLayer&, bool compositedChildrenOnly);
150     
151     // Whether layer's backing needs a graphics layer to do clipping by an ancestor (non-stacking-context parent with overflow).
152     bool clippedByAncestor(RenderLayer&) const;
153     // Whether layer's backing needs a graphics layer to clip z-order children of the given layer.
154     bool clipsCompositingDescendants(const RenderLayer&) const;
155
156     // Whether the given layer needs an extra 'contents' layer.
157     bool needsContentsCompositingLayer(const RenderLayer&) const;
158
159     bool supportsFixedRootBackgroundCompositing() const;
160     bool needsFixedRootBackgroundLayer(const RenderLayer&) const;
161     GraphicsLayer* fixedRootBackgroundLayer() const;
162     
163     // Return the bounding box required for compositing layer and its childern, relative to ancestorLayer.
164     // If layerBoundingBox is not 0, on return it contains the bounding box of this layer only.
165     LayoutRect calculateCompositedBounds(const RenderLayer&, const RenderLayer& ancestorLayer) const;
166
167     // Repaint the appropriate layers when the given RenderLayer starts or stops being composited.
168     void repaintOnCompositingChange(RenderLayer&);
169     
170     void repaintInCompositedAncestor(RenderLayer&, const LayoutRect&);
171     
172     // Notify us that a layer has been added or removed
173     void layerWasAdded(RenderLayer& parent, RenderLayer& child);
174     void layerWillBeRemoved(RenderLayer& parent, RenderLayer& child);
175
176     // Get the nearest ancestor layer that has overflow or clip, but is not a stacking context
177     RenderLayer* enclosingNonStackingClippingLayer(const RenderLayer&) const;
178
179     // Repaint parts of all composited layers that intersect the given absolute rectangle (or the entire layer if the pointer is null).
180     void repaintCompositedLayers(const IntRect* = 0);
181
182     // Returns true if the given layer needs it own backing store.
183     bool requiresOwnBackingStore(const RenderLayer&, const RenderLayer* compositingAncestorLayer, const LayoutRect& layerCompositedBoundsInAncestor, const LayoutRect& ancestorCompositedBounds) const;
184
185     RenderLayer& rootRenderLayer() const;
186     GraphicsLayer* rootGraphicsLayer() const;
187     GraphicsLayer* scrollLayer() const;
188     GraphicsLayer* clipLayer() const;
189     GraphicsLayer* rootContentLayer() const;
190
191 #if ENABLE(RUBBER_BANDING)
192     GraphicsLayer* headerLayer() const;
193     GraphicsLayer* footerLayer() const;
194 #endif
195
196     enum RootLayerAttachment {
197         RootLayerUnattached,
198         RootLayerAttachedViaChromeClient,
199         RootLayerAttachedViaEnclosingFrame
200     };
201
202     RootLayerAttachment rootLayerAttachment() const { return m_rootLayerAttachment; }
203     void updateRootLayerAttachment();
204     void updateRootLayerPosition();
205     
206     void setIsInWindow(bool);
207
208     void clearBackingForAllLayers();
209     
210     void layerBecameComposited(const RenderLayer&) { ++m_compositedLayerCount; }
211     void layerBecameNonComposited(const RenderLayer&);
212     
213 #if ENABLE(VIDEO)
214     // Use by RenderVideo to ask if it should try to use accelerated compositing.
215     bool canAccelerateVideoRendering(RenderVideo&) const;
216 #endif
217
218     // Walk the tree looking for layers with 3d transforms. Useful in case you need
219     // to know if there is non-affine content, e.g. for drawing into an image.
220     bool has3DContent() const;
221     
222     // Most platforms connect compositing layer trees between iframes and their parent document.
223     // Some (currently just Mac) allow iframes to do their own compositing.
224     static bool allowsIndependentlyCompositedFrames(const FrameView*);
225     bool shouldPropagateCompositingToEnclosingFrame() const;
226
227     static RenderLayerCompositor* frameContentsCompositor(RenderWidget*);
228     // Return true if the layers changed.
229     static bool parentFrameContentLayers(RenderWidget*);
230
231     // Update the geometry of the layers used for clipping and scrolling in frames.
232     void frameViewDidChangeLocation(const IntPoint& contentsOffset);
233     void frameViewDidChangeSize();
234     void frameViewDidScroll();
235     void frameViewDidAddOrRemoveScrollbars();
236     void frameViewDidLayout();
237     void rootFixedBackgroundsChanged();
238
239     void scrollingLayerDidChange(RenderLayer&);
240     void fixedRootBackgroundLayerChanged();
241
242     String layerTreeAsText(LayerTreeFlags);
243
244     virtual float deviceScaleFactor() const override;
245     virtual float contentsScaleMultiplierForNewTiles(const GraphicsLayer*) const override;
246     virtual float pageScaleFactor() const override;
247     virtual float zoomedOutPageScaleFactor() const override;
248
249     virtual void didCommitChangesForLayer(const GraphicsLayer*) const override;
250     virtual void notifyFlushBeforeDisplayRefresh(const GraphicsLayer*) override;
251
252     void layerTiledBackingUsageChanged(const GraphicsLayer*, bool /*usingTiledBacking*/);
253     
254     bool acceleratedDrawingEnabled() const { return m_acceleratedDrawingEnabled; }
255
256     void deviceOrPageScaleFactorChanged();
257
258     void windowScreenDidChange(PlatformDisplayID);
259
260     GraphicsLayer* layerForHorizontalScrollbar() const { return m_layerForHorizontalScrollbar.get(); }
261     GraphicsLayer* layerForVerticalScrollbar() const { return m_layerForVerticalScrollbar.get(); }
262     GraphicsLayer* layerForScrollCorner() const { return m_layerForScrollCorner.get(); }
263 #if ENABLE(RUBBER_BANDING)
264     GraphicsLayer* layerForOverhangAreas() const { return m_layerForOverhangAreas.get(); }
265     GraphicsLayer* layerForContentShadow() const { return m_contentShadowLayer.get(); }
266
267     GraphicsLayer* updateLayerForTopOverhangArea(bool wantsLayer);
268     GraphicsLayer* updateLayerForBottomOverhangArea(bool wantsLayer);
269     GraphicsLayer* updateLayerForHeader(bool wantsLayer);
270     GraphicsLayer* updateLayerForFooter(bool wantsLayer);
271 #endif
272
273     ScrollableArea* scrollableAreaForScrollLayerID(ScrollingNodeID) const;
274
275     void updateScrollCoordinatedStatus(RenderLayer&);
276     void removeFromScrollCoordinatedLayers(RenderLayer&);
277
278     void willRemoveScrollingLayer(RenderLayer&);
279     void didAddScrollingLayer(RenderLayer&);
280
281 #if PLATFORM(IOS)
282     void registerAllViewportConstrainedLayers();
283     void unregisterAllViewportConstrainedLayers();
284
285     void registerAllScrollingLayers();
286     void unregisterAllScrollingLayers();
287 #endif
288
289     void resetTrackedRepaintRects();
290     void setTracksRepaints(bool);
291
292     void setShouldReevaluateCompositingAfterLayout() { m_reevaluateCompositingAfterLayout = true; }
293
294     bool viewHasTransparentBackground(Color* backgroundColor = 0) const;
295
296     bool hasNonMainLayersWithTiledBacking() const { return m_layersWithTiledBackingCount; }
297
298     CompositingReasons reasonsForCompositing(const RenderLayer&) const;
299
300     void setLayerFlushThrottlingEnabled(bool);
301     void disableLayerFlushThrottlingTemporarilyForInteraction();
302     
303     void didPaintBacking(RenderLayerBacking*);
304
305     void setRootExtendedBackgroundColor(const Color&);
306     Color rootExtendedBackgroundColor() const { return m_rootExtendedBackgroundColor; }
307
308 private:
309     class OverlapMap;
310
311     // GraphicsLayerClient implementation
312     virtual void notifyAnimationStarted(const GraphicsLayer*, double) override { }
313     virtual void notifyFlushRequired(const GraphicsLayer*) override;
314     virtual void paintContents(const GraphicsLayer*, GraphicsContext&, GraphicsLayerPaintingPhase, const FloatRect&) override;
315     virtual void customPositionForVisibleRectComputation(const GraphicsLayer*, FloatPoint&) const override;
316     virtual bool isTrackingRepaints() const override;
317     
318     // GraphicsLayerUpdaterClient implementation
319     virtual void flushLayersSoon(GraphicsLayerUpdater*) override;
320
321     // Whether the given RL needs a compositing layer.
322     bool needsToBeComposited(const RenderLayer&, RenderLayer::ViewportConstrainedNotCompositedReason* = 0) const;
323     // Whether the layer has an intrinsic need for compositing layer.
324     bool requiresCompositingLayer(const RenderLayer&, RenderLayer::ViewportConstrainedNotCompositedReason* = 0) const;
325     // Whether the layer could ever be composited.
326     bool canBeComposited(const RenderLayer&) const;
327
328     // Make or destroy the backing for this layer; returns true if backing changed.
329     bool updateBacking(RenderLayer&, CompositingChangeRepaint shouldRepaint);
330
331     void clearBackingForLayerIncludingDescendants(RenderLayer&);
332     void setIsInWindowForLayerIncludingDescendants(RenderLayer&, bool isInWindow);
333
334     // Repaint the given rect (which is layer's coords), and regions of child layers that intersect that rect.
335     void recursiveRepaintLayer(RenderLayer&, const IntRect* = nullptr);
336
337     void addToOverlapMap(OverlapMap&, RenderLayer&, IntRect& layerBounds, bool& boundsComputed);
338     void addToOverlapMapRecursive(OverlapMap&, RenderLayer&, RenderLayer* ancestorLayer = nullptr);
339
340     void updateCompositingLayersTimerFired(Timer<RenderLayerCompositor>&);
341
342     // Returns true if any layer's compositing changed
343     void computeCompositingRequirements(RenderLayer* ancestorLayer, RenderLayer&, OverlapMap*, struct CompositingState&, bool& layersChanged, bool& descendantHas3DTransform);
344
345     void computeRegionCompositingRequirements(RenderNamedFlowFragment*, OverlapMap*, CompositingState&, bool& layersChanged, bool& anyDescendantHas3DTransform);
346
347     void computeCompositingRequirementsForNamedFlowFixed(RenderLayer&, OverlapMap*, CompositingState&, bool& layersChanged, bool& anyDescendantHas3DTransform);
348
349     // Recurses down the tree, parenting descendant compositing layers and collecting an array of child layers for the current compositing layer.
350     void rebuildCompositingLayerTree(RenderLayer&, Vector<GraphicsLayer*>& childGraphicsLayersOfEnclosingLayer, int depth);
351
352     // Recurses down the RenderFlowThread tree, parenting descendant compositing layers and collecting an array of child 
353     // layers for the current compositing layer corresponding to the anonymous region (that belongs to the region's parent).
354     void rebuildRegionCompositingLayerTree(RenderNamedFlowFragment*, Vector<GraphicsLayer*>& childList, int depth);
355
356     void rebuildCompositingLayerTreeForNamedFlowFixed(RenderLayer&, Vector<GraphicsLayer*>& childList, int depth);
357
358     // Recurses down the tree, updating layer geometry only.
359     void updateLayerTreeGeometry(RenderLayer&, int depth);
360     
361     // Hook compositing layers together
362     void setCompositingParent(RenderLayer& childLayer, RenderLayer* parentLayer);
363     void removeCompositedChildren(RenderLayer&);
364
365     bool layerHas3DContent(const RenderLayer&) const;
366     bool isRunningAcceleratedTransformAnimation(RenderLayerModelObject&) const;
367
368     void appendOverlayLayers(Vector<GraphicsLayer*>&);
369     bool hasAnyAdditionalCompositedLayers(const RenderLayer& rootLayer) const;
370
371     void ensureRootLayer();
372     void destroyRootLayer();
373
374     void attachRootLayer(RootLayerAttachment);
375     void detachRootLayer();
376     
377     void rootLayerAttachmentChanged();
378
379     void updateOverflowControlsLayers();
380
381     void updateScrollLayerPosition();
382
383     FloatPoint positionForClipLayer() const;
384
385     void notifyIFramesOfCompositingChange();
386
387     bool isFlushingLayers() const { return m_flushingLayers; }
388     
389     Page* page() const;
390     
391     GraphicsLayerFactory* graphicsLayerFactory() const;
392     ScrollingCoordinator* scrollingCoordinator() const;
393
394 #if USE(REQUEST_ANIMATION_FRAME_DISPLAY_MONITOR)
395     PassRefPtr<DisplayRefreshMonitor> createDisplayRefreshMonitor(PlatformDisplayID) const;
396 #endif
397
398     bool requiresCompositingForAnimation(RenderLayerModelObject&) const;
399     bool requiresCompositingForTransform(RenderLayerModelObject&) const;
400     bool requiresCompositingForBackfaceVisibility(RenderLayerModelObject&) const;
401     bool requiresCompositingForVideo(RenderLayerModelObject&) const;
402     bool requiresCompositingForCanvas(RenderLayerModelObject&) const;
403     bool requiresCompositingForPlugin(RenderLayerModelObject&) const;
404     bool requiresCompositingForFrame(RenderLayerModelObject&) const;
405     bool requiresCompositingForFilters(RenderLayerModelObject&) const;
406     bool requiresCompositingForScrollableFrame() const;
407     bool requiresCompositingForPosition(RenderLayerModelObject&, const RenderLayer&, RenderLayer::ViewportConstrainedNotCompositedReason* = 0) const;
408     bool requiresCompositingForOverflowScrolling(const RenderLayer&) const;
409     bool requiresCompositingForIndirectReason(RenderLayerModelObject&, bool hasCompositedDescendants, bool has3DTransformedDescendants, RenderLayer::IndirectCompositingReason&) const;
410
411 #if PLATFORM(IOS)
412     bool requiresCompositingForScrolling(const RenderLayer&) const;
413
414     void updateCustomLayersAfterFlush();
415
416     ChromeClient* chromeClient() const;
417
418 #endif
419
420     enum ScrollCoordinationReason {
421         FixedOrSticky = 1 << 0,
422         Scrolling = 1 << 1
423     };
424     typedef unsigned ScrollCoordinationReasons;
425
426     void updateScrollCoordinationForThisFrame(ScrollingNodeID);
427     ScrollingNodeID attachScrollingNode(RenderLayer&, ScrollingNodeType, ScrollingNodeID parentNodeID);
428     void updateScrollCoordinatedLayer(RenderLayer&, ScrollCoordinationReasons);
429     void detachScrollCoordinatedLayer(RenderLayer&);
430     void reattachSubframeScrollLayers();
431     
432     FixedPositionViewportConstraints computeFixedViewportConstraints(RenderLayer&) const;
433     StickyPositionViewportConstraints computeStickyViewportConstraints(RenderLayer&) const;
434
435     bool requiresScrollLayer(RootLayerAttachment) const;
436     bool requiresHorizontalScrollbarLayer() const;
437     bool requiresVerticalScrollbarLayer() const;
438     bool requiresScrollCornerLayer() const;
439 #if ENABLE(RUBBER_BANDING)
440     bool requiresOverhangAreasLayer() const;
441     bool requiresContentShadowLayer() const;
442 #endif
443
444     // True if the FrameView uses a ScrollingCoordinator.
445     bool hasCoordinatedScrolling() const;
446
447     bool isAsyncScrollableStickyLayer(const RenderLayer&, const RenderLayer** enclosingAcceleratedOverflowLayer = nullptr) const;
448     bool isViewportConstrainedFixedOrStickyLayer(const RenderLayer&) const;
449     
450     bool shouldCompositeOverflowControls() const;
451
452     void scheduleLayerFlushNow();
453     bool isThrottlingLayerFlushes() const;
454     void startInitialLayerFlushTimerIfNeeded();
455     void startLayerFlushTimerIfNeeded();
456     void layerFlushTimerFired(Timer<RenderLayerCompositor>&);
457
458     void paintRelatedMilestonesTimerFired(Timer<RenderLayerCompositor>&);
459
460 #if !LOG_DISABLED
461     const char* logReasonsForCompositing(const RenderLayer&);
462     void logLayerInfo(const RenderLayer&, int depth);
463 #endif
464
465     bool mainFrameBackingIsTiled() const;
466
467 private:
468     RenderView& m_renderView;
469     std::unique_ptr<GraphicsLayer> m_rootContentLayer;
470     Timer<RenderLayerCompositor> m_updateCompositingLayersTimer;
471
472     bool m_hasAcceleratedCompositing;
473     ChromeClient::CompositingTriggerFlags m_compositingTriggers;
474
475     int m_compositedLayerCount;
476     bool m_showDebugBorders;
477     bool m_showRepaintCounter;
478     bool m_acceleratedDrawingEnabled;
479
480     // When true, we have to wait until layout has happened before we can decide whether to enter compositing mode,
481     // because only then do we know the final size of plugins and iframes.
482     mutable bool m_reevaluateCompositingAfterLayout;
483
484     bool m_compositing;
485     bool m_compositingLayersNeedRebuild;
486     bool m_flushingLayers;
487     bool m_shouldFlushOnReattach;
488     bool m_forceCompositingMode;
489     bool m_inPostLayoutUpdate; // true when it's OK to trust layout information (e.g. layer sizes and positions)
490     bool m_subframeScrollLayersNeedReattach;
491
492     bool m_isTrackingRepaints; // Used for testing.
493
494     unsigned m_layersWithTiledBackingCount;
495
496     RootLayerAttachment m_rootLayerAttachment;
497
498     // Enclosing clipping layer for iframe content
499     std::unique_ptr<GraphicsLayer> m_clipLayer;
500     std::unique_ptr<GraphicsLayer> m_scrollLayer;
501
502 #if PLATFORM(IOS)
503     HashSet<RenderLayer*> m_scrollingLayers;
504     HashSet<RenderLayer*> m_scrollingLayersNeedingUpdate;
505 #endif
506     HashSet<RenderLayer*> m_scrollCoordinatedLayers;
507     HashSet<RenderLayer*> m_scrollCoordinatedLayersNeedingUpdate;
508
509     // Enclosing layer for overflow controls and the clipping layer
510     std::unique_ptr<GraphicsLayer> m_overflowControlsHostLayer;
511
512     // Layers for overflow controls
513     std::unique_ptr<GraphicsLayer> m_layerForHorizontalScrollbar;
514     std::unique_ptr<GraphicsLayer> m_layerForVerticalScrollbar;
515     std::unique_ptr<GraphicsLayer> m_layerForScrollCorner;
516 #if ENABLE(RUBBER_BANDING)
517     std::unique_ptr<GraphicsLayer> m_layerForOverhangAreas;
518     std::unique_ptr<GraphicsLayer> m_contentShadowLayer;
519     std::unique_ptr<GraphicsLayer> m_layerForTopOverhangArea;
520     std::unique_ptr<GraphicsLayer> m_layerForBottomOverhangArea;
521     std::unique_ptr<GraphicsLayer> m_layerForHeader;
522     std::unique_ptr<GraphicsLayer> m_layerForFooter;
523 #endif
524
525     std::unique_ptr<GraphicsLayerUpdater> m_layerUpdater; // Updates tiled layer visible area periodically while animations are running.
526
527     Timer<RenderLayerCompositor> m_layerFlushTimer;
528     bool m_layerFlushThrottlingEnabled;
529     bool m_layerFlushThrottlingTemporarilyDisabledForInteraction;
530     bool m_hasPendingLayerFlush;
531
532     Timer<RenderLayerCompositor> m_paintRelatedMilestonesTimer;
533
534 #if !LOG_DISABLED
535     int m_rootLayerUpdateCount;
536     int m_obligateCompositedLayerCount; // count of layer that have to be composited.
537     int m_secondaryCompositedLayerCount; // count of layers that have to be composited because of stacking or overlap.
538     double m_obligatoryBackingStoreBytes;
539     double m_secondaryBackingStoreBytes;
540 #endif
541
542     Color m_rootExtendedBackgroundColor;
543
544     HashMap<ScrollingNodeID, RenderLayer*> m_scrollingNodeToLayerMap;
545 };
546
547
548 } // namespace WebCore
549
550 #endif // RenderLayerCompositor_h