cc: Refactor content scale/bounds into draw properties

cc/image_layer.h

Index: cc/image_layer.h
diff --git a/cc/image_layer.h b/cc/image_layer.h
index f4f6cd7c2d88067acd71a7800ea01df585f94a6f..e9d1b09723127407d5fb3931c791a7f1193bd75f 100644
--- a/cc/image_layer.h
+++ b/cc/image_layer.h
@@ -21,8 +21,7 @@ public:
     virtual bool drawsContent() const OVERRIDE;
     virtual void setTexturePriorities(const PriorityCalculator&) OVERRIDE;
     virtual void update(ResourceUpdateQueue&, const OcclusionTracker*, RenderingStats&) OVERRIDE;
-    virtual float contentsScaleX() const OVERRIDE;
-    virtual float contentsScaleY() const OVERRIDE;
+    virtual void setIdealContentsScale(float ideal_contents_scale) OVERRIDE;
 
     void setBitmap(const SkBitmap& image);
 
@@ -34,7 +33,8 @@ private:
 
     virtual LayerUpdater* updater() const OVERRIDE;
     virtual void createUpdaterIfNeeded() OVERRIDE;
-    virtual gfx::Size contentBounds() const OVERRIDE;
+    float contentsScaleX() const;
+    float contentsScaleY() const;
 
     SkBitmap m_bitmap;