Add support for external video renderers in mojo.

media/mojo/services/mojo_renderer_service.h

Index: media/mojo/services/mojo_renderer_service.h
diff --git a/media/mojo/services/mojo_renderer_service.h b/media/mojo/services/mojo_renderer_service.h
index 7e81140b2e40a5a7328196bb26196f1d284e04db..35e47cd154dcef49577ea4214cfdae054cb93ae2 100644
--- a/media/mojo/services/mojo_renderer_service.h
+++ b/media/mojo/services/mojo_renderer_service.h
@@ -39,7 +39,8 @@ class MojoRendererService : public mojo::InterfaceImpl<mojo::MediaRenderer> {
   ~MojoRendererService() override;
 
   // mojo::MediaRenderer implementation.
-  void Initialize(mojo::DemuxerStreamPtr streams,
+  void Initialize(mojo::DemuxerStreamPtr audio,
+                  mojo::DemuxerStreamPtr video,
                   const mojo::Closure& callback) override;
   void Flush(const mojo::Closure& callback) override;
   void StartPlayingFrom(int64_t time_delta_usec) override;