[DO NOT COMMIT] Initial MediaPlayerRenderer plumbing and basic features

media/media_options.gni

Index: media/media_options.gni
diff --git a/media/media_options.gni b/media/media_options.gni
index 55f247be23834d266782b92b204ee96c792faf0e..6904a3ba270ae5a2e870541c567f24c163cbdc67 100644
--- a/media/media_options.gni
+++ b/media/media_options.gni
@@ -75,6 +75,11 @@ declare_args() {
   # Enable the TestMojoMediaClient to be used in MojoMediaApplication. This is
   # for testing only and will override the default platform MojoMediaClient.
   enable_test_mojo_media_client = false
+
+  # Enable and force 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|.
+  force_mojo_media_player_renderer = false
 }
 
 # Use a second declare_args() to pick up possible overrides of enable_mojo_media