[WIP] Adding support for <iframe>s to slimming paint.

Source/core/paint/ViewDisplayList.h

Index: Source/core/paint/ViewDisplayList.h
diff --git a/Source/core/paint/ViewDisplayList.h b/Source/core/paint/ViewDisplayList.h
index 582fca092c6ab36a8ace865f7a15784f69153bf9..e3aacfddcbbd0a3209432fe1c890138cb36f993d 100644
--- a/Source/core/paint/ViewDisplayList.h
+++ b/Source/core/paint/ViewDisplayList.h
@@ -48,6 +48,7 @@ public:
         ClipLayerFragmentSelection = 25,
         ClipLayerFragmentChildBlockBackgrounds = 26,
         EndClip = 27,
+        Translation = 28,
     };
 
     virtual ~DisplayItem() { }
@@ -92,6 +93,9 @@ public:
     void showDebugData() const;
 #endif
 
+    static ViewDisplayList& fromRenderObject(const RenderObject*);
+    static ViewDisplayList& fromRenderLayer(const RenderLayer*);
+
 private:
     bool isRepaint(PaintList::iterator, const DisplayItem&);
     // Update m_paintList with any invalidations or new paints.