Merge 122861 - Incorrect offset used for scrollWidth/Height calculation

Source/WebCore/rendering/RenderLayer.cpp

 /*
  * Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
  *
  * Portions are Copyright (C) 1998 Netscape Communications Corporation.
  *
  * Other contributors:
  *   Robert O'Callahan <roc+@cs.cmu.edu>
  *   David Baron <dbaron@fas.harvard.edu>
  *   Christian Biesinger <cbiesinger@web.de>
  *   Randall Jesup <rjesup@wgate.com>
@@ skipping 1562 matching lines @@
     }
 }
 
 void RenderLayer::scrollToOffset(int x, int y, ScrollOffsetClamping clamp)
 {
     if (clamp == ScrollOffsetClamped) {
         RenderBox* box = renderBox();
         if (!box)
             return;
 
-        int maxX = scrollWidth() - box->clientWidth();
-        int maxY = scrollHeight() - box->clientHeight();
+        int maxX = scrollWidth() - box->pixelSnappedClientWidth();
+        int maxY = scrollHeight() - box->pixelSnappedClientHeight();
 
         x = min(max(x, 0), maxX);
         y = min(max(y, 0), maxY);
     }
 
     IntPoint newScrollOffset(x, y);
     if (newScrollOffset != LayoutPoint(scrollXOffset(), scrollYOffset()))
         scrollToOffsetWithoutAnimation(newScrollOffset);
 }
 
@@ skipping 807 matching lines @@
         m_scrollCorner->setFrameRect(scrollCorner);
     if (m_resizer)
         m_resizer->setFrameRect(resizerCornerRect(this, borderBox));
 }
 
 int RenderLayer::scrollWidth() const
 {
     ASSERT(renderBox());
     if (m_scrollDimensionsDirty)
         const_cast<RenderLayer*>(this)->computeScrollDimensions();
-    return snapSizeToPixel(m_scrollSize.width(), renderBox()->clientLeft());
+    return snapSizeToPixel(m_scrollSize.width(), renderBox()->clientLeft() + renderBox()->x());
 }
 
 int RenderLayer::scrollHeight() const
 {
     ASSERT(renderBox());
     if (m_scrollDimensionsDirty)
         const_cast<RenderLayer*>(this)->computeScrollDimensions();
-    return snapSizeToPixel(m_scrollSize.height(), renderBox()->clientTop());
+    return snapSizeToPixel(m_scrollSize.height(), renderBox()->clientTop() + renderBox()->y());
 }
 
 LayoutUnit RenderLayer::overflowTop() const
 {
     RenderBox* box = renderBox();
     LayoutRect overflowRect(box->layoutOverflowRect());
     box->flipForWritingMode(overflowRect);
     return overflowRect.y();
 }
 
@@ skipping 2604 matching lines @@
     }
 }
 
 void showLayerTree(const WebCore::RenderObject* renderer)
 {
     if (!renderer)
         return;
     showLayerTree(renderer->enclosingLayer());
 }
 #endif