Make mojo renderer capable of supporting multiple streams/tracks

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 c088d5936d070cd098feb2b01f77b3cd0ccabbbb..d9bd5b6c12023477e2dd843c7a2c5522f187f2c0 100644
--- a/media/mojo/services/mojo_renderer_service.h
+++ b/media/mojo/services/mojo_renderer_service.h
@@ -63,8 +63,7 @@ class MEDIA_MOJO_EXPORT MojoRendererService
 
   // mojom::Renderer implementation.
   void Initialize(mojom::RendererClientAssociatedPtrInfo client,
-                  mojom::DemuxerStreamPtr audio,
-                  mojom::DemuxerStreamPtr video,
+                  base::Optional<std::vector<mojom::DemuxerStreamPtr>> streams,
                   const base::Optional<GURL>& media_url,
                   const base::Optional<GURL>& first_party_for_cookies,
                   const InitializeCallback& callback) final;