Fix paint invalidation rect of LayoutView

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

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009 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
  * 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 305 matching lines @@
     // Ditto when not in compositing mode.
     if (!usesCompositing())
         return LayoutBlockFlow::visualOverflowRect();
 
     // In normal compositing mode, LayoutView doesn't actually apply clipping
     // on its descendants. Instead their visual overflow is propagated to
     // compositor()->m_rootContentLayer for accelerated scrolling.
     return LayoutRect(documentRect());
 }
 
+LayoutRect LayoutView::localOverflowRectForPaintInvalidation() const
+{
+    // TODO(wangxianzhu): This is only required without rootLayerScrolls (though it is also correct
+    // but unnecessary with rootLayerScrolls) because of the special LayoutView overflow model.
+    return visualOverflowRect();
+}
+
 void LayoutView::mapLocalToAncestor(const LayoutBoxModelObject* ancestor, TransformState& transformState, MapCoordinatesFlags mode) const
 {
     if (!ancestor && mode & UseTransforms && shouldUseTransformFromContainer(0)) {
         TransformationMatrix t;
         getTransformFromContainer(0, LayoutSize(), t);
         transformState.applyTransform(t);
     }
 
     if ((mode & IsFixed) && m_frameView) {
         transformState.move(toIntSize(m_frameView->scrollPosition()));
@@ skipping 699 matching lines @@
     // ASSERT(!frame()->isMainFrame()) here. All main frame scrolling should
     // be handled by the ViewportScrollCallback.
 
     if (!frameView())
         return ScrollResult(false, false, delta.width(), delta.height());
 
     return frameView()->getScrollableArea()->userScroll(granularity, delta);
 }
 
 } // namespace blink