Pass accurate contentsScale to LayerImpl.

cc/layer_tree_host_unittest.cc

Index: cc/layer_tree_host_unittest.cc
diff --git a/cc/layer_tree_host_unittest.cc b/cc/layer_tree_host_unittest.cc
index 86be12240e0427791dada0797da779d21a307ac6..11173565089d96b2c7c7c9588443949bf0c0f5f6 100644
--- a/cc/layer_tree_host_unittest.cc
+++ b/cc/layer_tree_host_unittest.cc
@@ -1224,7 +1224,9 @@ class NoScaleContentLayer : public ContentLayer {
 public:
     static scoped_refptr<NoScaleContentLayer> create(ContentLayerClient* client) { return make_scoped_refptr(new NoScaleContentLayer(client)); }
 
-    virtual bool needsContentsScale() const OVERRIDE { return false; }
+    virtual IntSize contentBounds() const OVERRIDE { return bounds(); }
+    virtual float contentsScaleX() const OVERRIDE { return 1.0; }
+    virtual float contentsScaleY() const OVERRIDE { return 1.0; }
 
 private:
     explicit NoScaleContentLayer(ContentLayerClient* client)