Pad inval rects to compensate for Skia's hairline stroke

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 483 matching lines @@
       const PaintLayer* scrollParent,
       bool& owningLayerIsClipped,
       bool& owningLayerIsMasked);
 
   const 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);
 
+  // Returns the inval rect adjusted for subpixel accumulation and padded for
+  // safe rasterization.
+  IntRect adjustedInvalRect(const LayoutRect&) 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->
@@ skipping 177 matching lines @@
   // layer and the graphics layer because the scrolling contents layer is
   // clipped by the padding box.
   unsigned m_backgroundPaintsOntoGraphicsLayer : 1;
 
   friend class CompositedLayerMappingTest;
 };
 
 }  // namespace blink
 
 #endif  // CompositedLayerMapping_h