Let synchronized painting generate correct paint invalidation rects

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 105 matching lines @@
     GraphicsLayer* childTransformLayer() const { return m_childTransformLayer.get(); }
 
     GraphicsLayer* squashingContainmentLayer() const { return m_squashingContainmentLayer.get(); }
     GraphicsLayer* squashingLayer() const { return m_squashingLayer.get(); }
 
     void setSquashingContentsNeedDisplay();
     void setContentsNeedDisplay();
     // LayoutRect is in the coordinate space of the layer's layout object.
     void setContentsNeedDisplayInRect(const LayoutRect&, PaintInvalidationReason);
 
-    void invalidateDisplayItemClient(const DisplayItemClientWrapper&, PaintInvalidationReason, const LayoutRect& previousPaintInvalidationRect, const LayoutRect& newPaintInvalidationRect);
-    void invalidateDisplayItemClientOnScrollingContentsLayer(const DisplayItemClientWrapper&, PaintInvalidationReason, const LayoutRect& previousPaintInvalidationRect, const LayoutRect& newPaintInvalidationRect);
+    // If |visualRect| is not nullptr, it contains all pixels that might be painted by the display item client,
+    // in coordinate space of the layer's layout object.
+    // |visualRect| can be nullptr if we know it's unchanged and PaintController has cached the previous value.
+    void invalidateDisplayItemClient(const DisplayItemClientWrapper&, PaintInvalidationReason, const LayoutRect* visualRect);
+    void invalidateDisplayItemClientOnScrollingContentsLayer(const DisplayItemClientWrapper&, PaintInvalidationReason, const LayoutRect* visualRect);
 
     // Notification from the layoutObject that its content changed.
     void contentChanged(ContentChangeType);
 
     LayoutRect compositedBounds() const { return m_compositedBounds; }
     IntRect pixelSnappedCompositedBounds() const;
 
     void positionOverflowControlsLayers();
 
     // Returns true if the assignment actually changed the assigned squashing layer.
@@ skipping 295 matching lines @@
 
     unsigned m_backgroundLayerPaintsFixedRootBackground : 1;
     unsigned m_scrollingContentsAreEmpty : 1;
 
     friend class CompositedLayerMappingTest;
 };
 
 } // namespace blink
 
 #endif // CompositedLayerMapping_h