Get rid of one-off code in ScrollingCoordinator to handle graphics layer offsets.

Source/core/testing/Internals.cpp

 /*
  * Copyright (C) 2012 Google Inc. All rights reserved.
  * Copyright (C) 2013 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:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
@@ skipping 1286 matching lines @@
     unsigned count = 0;
     for (TouchEventTargetSet::const_iterator iter = touchHandlers->begin(); iter != touchHandlers->end(); ++iter)
         count += iter->value;
     return count;
 }
 
 static RenderLayer* findRenderLayerForGraphicsLayer(RenderLayer* searchRoot, GraphicsLayer* graphicsLayer, IntSize* layerOffset, String* layerType)
 {
     *layerOffset = IntSize();
     if (searchRoot->hasCompositedLayerMapping() && graphicsLayer == searchRoot->compositedLayerMapping()->mainGraphicsLayer()) {
-        CompositedLayerMappingPtr compositedLayerMapping = searchRoot->compositedLayerMapping();
-        LayoutSize offset = compositedLayerMapping->contentOffsetInCompositingLayer();
-        *layerOffset = IntSize(offset.width(), offset.height());
+        LayoutRect rect;
+        RenderLayer::mapRectToPaintBackingCoordinates(searchRoot->renderer(), rect);
+        *layerOffset = IntSize(rect.x(), rect.y());
         return searchRoot;
     }
 
     GraphicsLayer* layerForScrolling = searchRoot->scrollableArea() ? searchRoot->scrollableArea()->layerForScrolling() : 0;
     if (graphicsLayer == layerForScrolling) {
         *layerType = "scrolling";
         return searchRoot;
     }
 
     if (searchRoot->compositingState() == PaintsIntoGroupedBacking) {
         GraphicsLayer* squashingLayer = searchRoot->groupedMapping()->squashingLayer();
         if (graphicsLayer == squashingLayer) {
             *layerType ="squashing";
-            *layerOffset = -searchRoot->offsetFromSquashingLayerOrigin();
+            LayoutRect rect;
+            RenderLayer::mapRectToPaintBackingCoordinates(searchRoot->renderer(), rect);
+            *layerOffset = IntSize(rect.x(), rect.y());
             return searchRoot;
         }
     }
 
     GraphicsLayer* layerForHorizontalScrollbar = searchRoot->scrollableArea() ? searchRoot->scrollableArea()->layerForHorizontalScrollbar() : 0;
     if (graphicsLayer == layerForHorizontalScrollbar) {
         *layerType = "horizontalScrollbar";
         return searchRoot;
     }
 
@@ skipping 1000 matching lines @@
     }
     networkStateNotifier().setWebConnectionTypeForTest(webtype);
 }
 
 unsigned Internals::countHitRegions(CanvasRenderingContext2D* context)
 {
     return context->hitRegionsCount();
 }
 
 } // namespace WebCore