Introduce Layout*::adjustVisualRectForRasterEffects and use it for SVG hairlines.

third_party/WebKit/Source/core/layout/LayoutObject.h

 /*
  * Copyright (C) 2000 Lars Knoll (knoll@kde.org)
  *           (C) 2000 Antti Koivisto (koivisto@kde.org)
  *           (C) 2000 Dirk Mueller (mueller@kde.org)
  *           (C) 2004 Allan Sandfeld Jensen (kde@carewolf.com)
  * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2012 Apple Inc.
  *               All rights reserved.
  * Copyright (C) 2009 Google Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
@@ skipping 1845 matching lines @@
   // Overrides should call the superclass at the start. |oldStyle| will be 0 the
   // first time this function is called.
   virtual void styleDidChange(StyleDifference, const ComputedStyle* oldStyle);
   void propagateStyleToAnonymousChildren();
   // Return true for objects that don't want style changes automatically
   // propagated via propagateStyleToAnonymousChildren(), but rather rely on
   // other custom mechanisms (if they need to be notified of parent style
   // changes at all).
   virtual bool anonymousHasStylePropagationOverride() { return false; }
 
+  // Allows objects to adjust |visualEffect|, which is in the space of the
+  // paint invalidation container, for any special raster effects that might
+  // expand the rastered pixel area.
+  virtual void adjustVisualRectForRasterEffects(LayoutRect& visualRect) const {}
+
  protected:
   // This function is called before calling the destructor so that some clean-up
   // can happen regardless of whether they call a virtual function or not. As a
   // rule of thumb, this function should be preferred to the destructor. See
   // destroy() that is the one calling willBeDestroyed().
   //
   // There are 2 types of destructions: regular destructions and tree tear-down.
   // Regular destructions happen when the renderer is not needed anymore (e.g.
   // 'display' changed or the DOM Node was removed).
   // Tree tear-down is when the whole tree destroyed during navigation. It is
@@ skipping 721 matching lines @@
 CORE_EXPORT void showLineTree(const blink::LayoutObject*);
 CORE_EXPORT void showLayoutTree(const blink::LayoutObject* object1);
 // We don't make object2 an optional parameter so that showLayoutTree
 // can be called from gdb easily.
 CORE_EXPORT void showLayoutTree(const blink::LayoutObject* object1,
                                 const blink::LayoutObject* object2);
 
 #endif
 
 #endif  // LayoutObject_h