Update PaintLayer size during layout, not after.

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

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2007 David Smith (catfish.man@gmail.com)
  * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010 Apple Inc.
  *               All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
@@ skipping 394 matching lines @@
 
   bool HitTestOverflowControl(HitTestResult&,
                               const HitTestLocation&,
                               const LayoutPoint& adjusted_location) override;
   bool HitTestChildren(HitTestResult&,
                        const HitTestLocation& location_in_container,
                        const LayoutPoint& accumulated_offset,
                        HitTestAction) override;
   void UpdateHitTestResult(HitTestResult&, const LayoutPoint&) override;
 
-  void UpdateAfterLayout();
+  void UpdateAfterLayout() override;
 
   void StyleWillChange(StyleDifference,
                        const ComputedStyle& new_style) override;
   void StyleDidChange(StyleDifference, const ComputedStyle* old_style) override;
   void UpdateFromStyle() override;
 
   // Returns true if non-visible overflow should be respected. Otherwise
   // hasOverflowClip() will be false and we won't create scrollable area for
   // this object even if overflow is non-visible.
   virtual bool AllowsOverflowClip() const;
@@ skipping 144 matching lines @@
   // TODO(lunalu): Temporary in order to ensure compatibility with existing
   // layout test results.
   virtual void AdjustChildDebugRect(LayoutRect&) const {}
 };
 
 DEFINE_LAYOUT_OBJECT_TYPE_CASTS(LayoutBlock, IsLayoutBlock());
 
 }  // namespace blink
 
 #endif  // LayoutBlock_h