Use recomputed interest rect only if it changed enough

third_party/WebKit/Source/core/layout/compositing/PaintLayerCompositor.h

 /*
  * Copyright (C) 2009 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 134 matching lines @@
 
     String layerTreeAsText(LayerTreeFlags);
 
     GraphicsLayer* layerForHorizontalScrollbar() const { return m_layerForHorizontalScrollbar.get(); }
     GraphicsLayer* layerForVerticalScrollbar() const { return m_layerForVerticalScrollbar.get(); }
     GraphicsLayer* layerForScrollCorner() const { return m_layerForScrollCorner.get(); }
 
     void resetTrackedPaintInvalidationRects();
     void setTracksPaintInvalidations(bool);
 
-    String debugName(const GraphicsLayer*) override;
+    String debugName(const GraphicsLayer*) const override;
     DocumentLifecycle& lifecycle() const;
 
     bool needsUpdateDescendantDependentFlags() const { return m_needsUpdateDescendantDependentFlags; }
     void setNeedsUpdateDescendantDependentFlags() { m_needsUpdateDescendantDependentFlags = true; }
 
     void updatePotentialCompositingReasonsFromStyle(PaintLayer*);
 
     // Whether the layer could ever be composited.
     bool canBeComposited(const PaintLayer*) const;
 
     // FIXME: Move allocateOrClearCompositedLayerMapping to CompositingLayerAssigner once we've fixed
     // the compositing chicken/egg issues.
     bool allocateOrClearCompositedLayerMapping(PaintLayer*, CompositingStateTransitionType compositedLayerUpdate);
 
     void updateDirectCompositingReasons(PaintLayer*);
 
     bool inOverlayFullscreenVideo() const { return m_inOverlayFullscreenVideo; }
 
 private:
 #if ENABLE(ASSERT)
     void assertNoUnresolvedDirtyBits();
 #endif
 
     // GraphicsLayerClient implementation
-    void paintContents(const GraphicsLayer*, GraphicsContext&, GraphicsLayerPaintingPhase, const IntRect*) const override;
+    IntRect computeInterestRect(const GraphicsLayer*, const IntRect&) const override;
+    void paintContents(const GraphicsLayer*, GraphicsContext&, GraphicsLayerPaintingPhase, const IntRect& interestRect) const override;
 
     bool isTrackingPaintInvalidations() const override;
 
     void updateWithoutAcceleratedCompositing(CompositingUpdateType);
     void updateIfNeeded();
 
     void ensureRootLayer();
     void destroyRootLayer();
 
     void attachRootLayer(RootLayerAttachment);
@@ skipping 52 matching lines @@
 
     // Layers for overflow controls
     OwnPtr<GraphicsLayer> m_layerForHorizontalScrollbar;
     OwnPtr<GraphicsLayer> m_layerForVerticalScrollbar;
     OwnPtr<GraphicsLayer> m_layerForScrollCorner;
 };
 
 } // namespace blink
 
 #endif // PaintLayerCompositor_h