Move viewport actions into an ApplyScroll callback.

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 1014 matching lines @@
         setHasBoxDecorationBackground(true);
 }
 
 bool LayoutView::allowsOverflowClip() const
 {
     return document().settings() && document().settings()->rootLayerScrolls();
 }
 
 ScrollResult LayoutView::scroll(ScrollGranularity granularity, const FloatSize& delta)
 {
+    // TODO(bokan): This should never get called on the main frame but it
+    // currently does via the Windows pan scrolling path. That should go through
+    // a more normalized EventHandler-like scrolling path and we should
+    // ASSERT(!frame()->isMainFrame()) here. All main frame scrolling should
+    // be handled by the ViewportScrollCallback.
+
     if (!frameView())
-        return ScrollResult();
+        return ScrollResult(false, false, delta.width(), delta.height());
 
-    return frame()->applyScrollDelta(granularity, delta, false);
+    return frameView()->getScrollableArea()->userScroll(granularity, delta);
 }
 
 } // namespace blink