Update PaintLayer size during layout, not after.

third_party/WebKit/Source/web/ChromeClientImpl.h

 /*
  * Copyright (C) 2009 Google Inc. All rights reserved.
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
@@ skipping 101 matching lines @@
   void InvalidateRect(const IntRect&) override;
   void ScheduleAnimation(LocalFrame*) override;
   IntRect ViewportToScreen(const IntRect&, const FrameViewBase*) const override;
   float WindowToViewportScalar(const float) const override;
   WebScreenInfo GetScreenInfo() const override;
   WTF::Optional<IntRect> VisibleContentRectForPainting() const override;
   void ContentsSizeChanged(LocalFrame*, const IntSize&) const override;
   void PageScaleFactorChanged() const override;
   float ClampPageScaleFactorToLimits(float scale) const override;
   void MainFrameScrollOffsetChanged() const override;
+  void ResizeAfterLayout(LocalFrame*) const override;
   void LayoutUpdated(LocalFrame*) const override;
   void ShowMouseOverURL(const HitTestResult&) override;
   void SetToolTip(LocalFrame&, const String&, TextDirection) override;
   void DispatchViewportPropertiesDidChange(
       const ViewportDescription&) const override;
   void PrintDelegate(LocalFrame*) override;
   void AnnotatedRegionsChanged() override;
   ColorChooser* OpenColorChooser(LocalFrame*,
                                  ColorChooserClient*,
                                  const Color&) override;
@@ skipping 119 matching lines @@
 
 DEFINE_TYPE_CASTS(ChromeClientImpl,
                   ChromeClient,
                   client,
                   client->IsChromeClientImpl(),
                   client.IsChromeClientImpl());
 
 }  // namespace blink
 
 #endif