[chromecast] Enable Mojo javascript bindings for cast_shell

chromecast/renderer/cast_content_renderer_client.h

Index: chromecast/renderer/cast_content_renderer_client.h
diff --git a/chromecast/renderer/cast_content_renderer_client.h b/chromecast/renderer/cast_content_renderer_client.h
index 5d4101b78ac5d7439e76de5c68d680f3287df123..1c9b91cde41e612ce40fe5de61a3acddfc7bb020 100644
--- a/chromecast/renderer/cast_content_renderer_client.h
+++ b/chromecast/renderer/cast_content_renderer_client.h
@@ -25,6 +25,10 @@ class MediaCapsObserverImpl;
 }
 
 namespace shell {
+class CastGinRunner;
+class CastRenderThreadObserver;
+
+void ExecuteJavaScript(content::RenderFrame* render_frame, int resourceId);
 
 class CastContentRendererClient : public content::ContentRendererClient {
  public:
@@ -44,6 +48,7 @@ class CastContentRendererClient : public content::ContentRendererClient {
   void DeferMediaLoad(content::RenderFrame* render_frame,
                       bool render_frame_has_played_media_before,
                       const base::Closure& closure) override;
+  void RunScriptsAtDocumentStart(content::RenderFrame* render_frame) override;
 
  protected:
   CastContentRendererClient();