Use recomputed interest rect only if it changed enough

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

 /*
  * Copyright (C) 2009, 2010, 2011 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 136 matching lines @@
     void finishAccumulatingSquashingLayers(size_t nextSquashedLayerIndex);
     void updateRenderingContext();
     void updateShouldFlattenTransform();
 
     // GraphicsLayerClient interface
     void notifyAnimationStarted(const GraphicsLayer*, double monotonicTime, int group) override;
     void notifyFirstPaint() override;
     void notifyFirstTextPaint() override;
     void notifyFirstImagePaint() override;
 
-    void paintContents(const GraphicsLayer*, GraphicsContext&, GraphicsLayerPaintingPhase, const IntRect* clip) const override;
+    IntRect computeInterestRect(const GraphicsLayer*, const IntRect& previousInterestRect) const override;
+    bool needsRepaint() const override;
+    void paintContents(const GraphicsLayer*, GraphicsContext&, GraphicsLayerPaintingPhase, const IntRect& interestRect) const override;
+
     bool isTrackingPaintInvalidations() const override;
 
 #if ENABLE(ASSERT)
     void verifyNotPainting() override;
 #endif
 
     LayoutRect contentsBox() const;
 
     GraphicsLayer* layerForHorizontalScrollbar() const { return m_layerForHorizontalScrollbar.get(); }
     GraphicsLayer* layerForVerticalScrollbar() const { return m_layerForVerticalScrollbar.get(); }
@@ skipping 19 matching lines @@
     bool needsGraphicsLayerUpdate() { return m_pendingUpdateScope > GraphicsLayerUpdateNone; }
     void setNeedsGraphicsLayerUpdate(GraphicsLayerUpdateScope scope) { m_pendingUpdateScope = std::max(static_cast<GraphicsLayerUpdateScope>(m_pendingUpdateScope), scope); }
     void clearNeedsGraphicsLayerUpdate() { m_pendingUpdateScope = GraphicsLayerUpdateNone; }
 
     GraphicsLayerUpdater::UpdateType updateTypeForChildren(GraphicsLayerUpdater::UpdateType) const;
 
 #if ENABLE(ASSERT)
     void assertNeedsToUpdateGraphicsLayerBitsCleared() {  ASSERT(m_pendingUpdateScope == GraphicsLayerUpdateNone); }
 #endif
 
-    String debugName(const GraphicsLayer*) override;
+    String debugName(const GraphicsLayer*) const override;
 
     LayoutSize contentOffsetInCompositingLayer() const;
 
     LayoutPoint squashingOffsetFromTransformedAncestor()
     {
         return m_squashingLayerOffsetFromTransformedAncestor;
     }
 
     // If there is a squashed layer painting into this CLM that is an ancestor of the given LayoutObject, return it. Otherwise return nullptr.
     const GraphicsLayerPaintInfo* containingSquashedLayer(const LayoutObject*, unsigned maxSquashedLayerIndex);
 
     void updateScrollingBlockSelection();
 
     DisplayItemClient displayItemClient() const { return toDisplayItemClient(this); }
     String debugName() const { return "CompositedLayerMapping for " + owningLayer().debugName(); }
 
 private:
-    static IntRect computeInterestRect(const GraphicsLayer*, LayoutObject* owningLayoutObject);
+    static IntRect recomputeInterestRect(const GraphicsLayer*, LayoutObject* owningLayoutObject);
     static bool interestRectChangedEnoughToRepaint(const IntRect& previousInterestRect, const IntRect& newInterestRect, const IntSize& layerSize);
 
     static const GraphicsLayerPaintInfo* containingSquashedLayer(const LayoutObject*,  const Vector<GraphicsLayerPaintInfo>& layers, unsigned maxSquashedLayerIndex);
 
     // Helper methods to updateGraphicsLayerGeometry:
     void computeGraphicsLayerParentLocation(const PaintLayer* compositingContainer, const IntRect& ancestorCompositingBounds, IntPoint& graphicsLayerParentLocation);
     void updateSquashingLayerGeometry(const LayoutPoint& offsetFromCompositedAncestor, const IntPoint& graphicsLayerParentLocation, const PaintLayer& referenceLayer, Vector<GraphicsLayerPaintInfo>& layers, GraphicsLayer*, LayoutPoint* offsetFromTransformedAncestor, Vector<PaintLayer*>& layersNeedingPaintInvalidation);
     void updateMainGraphicsLayerGeometry(const IntRect& relativeCompositingBounds, const IntRect& localCompositingBounds, const IntPoint& graphicsLayerParentLocation);
     void updateAncestorClippingLayerGeometry(const PaintLayer* compositingContainer, const IntPoint& snappedOffsetFromCompositedAncestor, IntPoint& graphicsLayerParentLocation);
     void updateOverflowControlsHostLayerGeometry(const PaintLayer* compositingStackingContext, const PaintLayer* compositingContainer);
@@ skipping 83 matching lines @@
     // Return true if |m_owningLayer|'s compositing ancestor is not a descendant (inclusive) of the
     // clipping container for |m_owningLayer|.
     bool owningLayerClippedByLayerNotAboveCompositedAncestor(PaintLayer* scrollParent);
 
     PaintLayer* scrollParent();
 
     // Clear the groupedMapping entry on the layer at the given index, only if that layer does
     // not appear earlier in the set of layers for this object.
     bool invalidateLayerIfNoPrecedingEntry(size_t);
 
-    void paintContentsInternal(const GraphicsLayer*, GraphicsContext&, GraphicsLayerPaintingPhase, const IntRect& interestRect) const;
-
     PaintLayer& m_owningLayer;
 
     // The hierarchy of layers that is maintained by the CompositedLayerMapping looks like this:
     //
     //  + m_ancestorClippingLayer [OPTIONAL]
     //    + m_graphicsLayer
     //      + m_childTransformLayer [OPTIONAL]
     //      | + m_childContainmentLayer [OPTIONAL] <-OR-> m_scrollingLayer [OPTIONAL]
     //      |                                             + m_scrollingContentsLayer [Present iff m_scrollingLayer is present]
     //      |                                               + m_scrollingBlockSelectionLayer [Present iff m_scrollingLayer is present]
@@ skipping 103 matching lines @@
 
     LayoutSize m_contentOffsetInCompositingLayer;
     unsigned m_contentOffsetInCompositingLayerDirty : 1;
 
     unsigned m_pendingUpdateScope : 2;
     unsigned m_isMainFrameLayoutViewLayer : 1;
 
     unsigned m_backgroundLayerPaintsFixedRootBackground : 1;
     unsigned m_scrollingContentsAreEmpty : 1;
 
-    mutable IntRect m_previousPaintInterestRect;
-
     friend class CompositedLayerMappingTest;
 };
 
 } // namespace blink
 
 #endif // CompositedLayerMapping_h