Finish the rename from cc::GraphicsContext to cc::OutputSurface

cc/layer_impl.h

Index: cc/layer_impl.h
diff --git a/cc/layer_impl.h b/cc/layer_impl.h
index ce22ed6f5b52e5c7a4da3a17fe0c08df52fb5599..886be2196ef33ebca564f2c2328e831e61c3c3f8 100644
--- a/cc/layer_impl.h
+++ b/cc/layer_impl.h
@@ -276,10 +276,10 @@ public:
 
     virtual void didUpdateTransforms() { }
 
-    // Indicates that the context previously used to render this layer
+    // Indicates that the surface previously used to render this layer
     // was lost and that a new one has been created. Won't be called
-    // until the new context has been created successfully.
-    virtual void didLoseContext();
+    // until the new surface has been created successfully.
+    virtual void didLoseOutputSurface();
 
     ScrollbarAnimationController* scrollbarAnimationController() const { return m_scrollbarAnimationController.get(); }