Enable builtin Mojo JS modules in layout tests

content/renderer/mojo_bindings_controller.h

Index: content/renderer/mojo_bindings_controller.h
diff --git a/content/renderer/mojo_bindings_controller.h b/content/renderer/mojo_bindings_controller.h
index 3ebb744cb06f47704c56c16ecc99018c6209e3f0..9d4ac9b9630ade7f4a7ecbc6b1af97ee05d8568d 100644
--- a/content/renderer/mojo_bindings_controller.h
+++ b/content/renderer/mojo_bindings_controller.h
@@ -28,7 +28,7 @@ class MojoBindingsController
     : public RenderFrameObserver,
       public RenderFrameObserverTracker<MojoBindingsController> {
  public:
-  explicit MojoBindingsController(RenderFrame* render_frame);
+  MojoBindingsController(RenderFrame* render_frame, bool for_layout_tests);
 
  private:
   ~MojoBindingsController() override;
@@ -44,6 +44,8 @@ class MojoBindingsController
   void DidCreateDocumentElement() override;
   void DidClearWindowObject() override;
 
+  const bool for_layout_tests_;
+
   DISALLOW_COPY_AND_ASSIGN(MojoBindingsController);
 };