Unifies ScrollView and RenderLayer to use non-shifted [minPos, maxPos] scroll offset

Source/core/platform/graphics/chromium/GraphicsLayerChromium.cpp

 /*
  * Copyright (C) 2010 Google Inc. All rights reserved.
  * Copyright (C) 2009 Apple Inc. All rights reserved.
  *
  * 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 563 matching lines @@
 }
 
 void GraphicsLayerChromium::notifyAnimationFinished(double)
 {
     // Do nothing.
 }
 
 void GraphicsLayerChromium::didScroll()
 {
     if (m_scrollableArea)
-        m_scrollableArea->scrollToOffsetWithoutAnimation(IntPoint(m_layer->layer()->scrollPosition()));
+        m_scrollableArea->scrollToOffsetWithoutAnimation(m_scrollableArea->minimumScrollPosition() + toIntSize(m_layer->layer()->scrollPosition()));
 }
 
 void GraphicsLayerChromium::reportMemoryUsage(MemoryObjectInfo* memoryObjectInfo) const
 {
     MemoryClassInfo info(memoryObjectInfo, this, PlatformMemoryTypes::Layers);
     GraphicsLayer::reportMemoryUsage(memoryObjectInfo);
     info.addMember(m_nameBase, "nameBase");
     info.addMember(m_layer, "layer");
     info.addMember(m_transformLayer, "transformLayer");
     info.addMember(m_imageLayer, "imageLayer");
     info.addMember(m_contentsLayer, "contentsLayer");
     info.addMember(m_linkHighlight, "linkHighlight");
     info.addMember(m_opaqueRectTrackingContentLayerDelegate, "opaqueRectTrackingContentLayerDelegate");
     info.addMember(m_animationIdMap, "animationIdMap");
     info.addMember(m_scrollableArea, "scrollableArea");
 }
 
 void GraphicsLayerChromium::setAnimationDelegateForLayer(WebKit::WebLayer* layer)
 {
     layer->setAnimationDelegate(this);
 }
 
 } // namespace WebCore