Register MediaPlayerRenderer service

media/media_options.gni

Index: media/media_options.gni
diff --git a/media/media_options.gni b/media/media_options.gni
index d6ab4f4249fdf03b06e294cc4f537fe282e66ab1..e0706bcbd39a5bbd863dc1c6bca2f59bef5495e2 100644
--- a/media/media_options.gni
+++ b/media/media_options.gni
@@ -73,6 +73,11 @@ declare_args() {
   # the media pipeline and corresponding services will hosted in the selected
   # remote process (e.g. "utility" process, see |mojo_media_host|).
   enable_mojo_media = is_android || is_chromecast
+
+  # Enable the use of the Mojo MediaPlayerRenderer.
+  # This flag is unafected by the |mojo_media_services|, because the service
+  # will always live in the browser process, regarless of |mojo_media_host|.
+  enable_mojo_media_player_renderer = false
 }
 
 # Use a second declare_args() to pick up possible overrides of enable_mojo_media