Update PaintLayer size during layout, not after.

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

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2006 Apple Computer, Inc.
  *
  * 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
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
@@ skipping 98 matching lines @@
 
   int ViewLogicalWidth(IncludeScrollbarsInRect = kExcludeScrollbars) const;
   int ViewLogicalHeight(IncludeScrollbarsInRect = kExcludeScrollbars) const;
 
   LayoutUnit ViewLogicalHeightForPercentages() const;
 
   float ZoomFactor() const;
 
   FrameView* GetFrameView() const { return frame_view_; }
 
+  void UpdateAfterLayout() override;
+
   // See comments for the equivalent method on LayoutObject.
   bool MapToVisualRectInAncestorSpace(const LayoutBoxModelObject* ancestor,
                                       LayoutRect&,
                                       MapCoordinatesFlags mode,
                                       VisualRectFlags) const;
 
   // |ancestor| can be nullptr, which will map the rect to the main frame's
   // space, even if the main frame is remote (or has intermediate remote
   // frames in the chain).
   bool MapToVisualRectInAncestorSpaceInternal(
@@ skipping 167 matching lines @@
   unsigned hit_test_count_;
   unsigned hit_test_cache_hits_;
   Persistent<HitTestCache> hit_test_cache_;
 };
 
 DEFINE_LAYOUT_OBJECT_TYPE_CASTS(LayoutView, IsLayoutView());
 
 }  // namespace blink
 
 #endif  // LayoutView_h