Revert 158386 - Revert 158362 - Support high DPI scrollbar on top level web frame.

cc/LayerChromium.h

Index: cc/LayerChromium.h
===================================================================
--- cc/LayerChromium.h	(revision 158397)
+++ cc/LayerChromium.h	(working copy)
@@ -232,6 +232,7 @@
     void setContentsScale(float);
 
     // When true, the layer's contents are not scaled by the current page scale factor.
+    // setBoundsContainPageScale recursively sets the value on all child layers.
     void setBoundsContainPageScale(bool);
     bool boundsContainPageScale() const { return m_boundsContainPageScale; }
 
@@ -273,6 +274,8 @@
 
     void setNeedsCommit();
 
+    IntRect layerRectToContentRect(const WebKit::WebRect& layerRect);
+
     // This flag is set when layer need repainting/updating.
     bool m_needsDisplay;