Expose mojo bindings to subframes in layout tests.

content/renderer/render_frame_impl.h

Index: content/renderer/render_frame_impl.h
diff --git a/content/renderer/render_frame_impl.h b/content/renderer/render_frame_impl.h
index 0d7a3fabc15ea251ec30aa17976476ce96258d90..b554ead998149fb3ce14a61c150947127da1abed 100644
--- a/content/renderer/render_frame_impl.h
+++ b/content/renderer/render_frame_impl.h
@@ -645,10 +645,11 @@ class CONTENT_EXPORT RenderFrameImpl
   // Sends the current frame's navigation state to the browser.
   void SendUpdateState();
 
-  // Creates a MojoBindingsController to allow WebUI documents to communicate
-  // with the browser process. If |for_layout_tests| is true, the module system
-  // is exposed on a global "mojo" object rather than "define".
-  void EnableMojoBindings(bool for_layout_tests);
+  // Creates a MojoBindingsController if Mojo bindings have been enabled for
+  // this frame. For WebUI, this allows the page to communicate with the browser
+  // process; for layout tests, this allows the test to mock out services at
+  // the Mojo IPC layer.
+  void MaybeEnableMojoBindings();
 
  protected:
   explicit RenderFrameImpl(const CreateParams& params);