[Chromecast] Add a custom CastMediaClient for Chromecast

chromecast/renderer/cast_content_renderer_client.cc

Index: chromecast/renderer/cast_content_renderer_client.cc
diff --git a/chromecast/renderer/cast_content_renderer_client.cc b/chromecast/renderer/cast_content_renderer_client.cc
index ed543fa659b3f79d45dddd45b50fc8ad990bd4fb..d8f655b8ba7e437b4ce6105686f59fb0de4a7551 100644
--- a/chromecast/renderer/cast_content_renderer_client.cc
+++ b/chromecast/renderer/cast_content_renderer_client.cc
@@ -11,6 +11,7 @@
 #include "base/strings/string_number_conversions.h"
 #include "build/build_config.h"
 #include "chromecast/base/chromecast_switches.h"
+#include "chromecast/common/media/cast_media_client.h"
 #include "chromecast/crash/cast_crash_keys.h"
 #include "chromecast/media/base/media_caps.h"
 #include "chromecast/renderer/cast_media_load_deferrer.h"
@@ -73,6 +74,8 @@ void CastContentRendererClient::RenderThreadStarted() {
     }
   }
 
+  chromecast::media::CastMediaClient::Initialize();
+
   cast_observer_.reset(new CastRenderThreadObserver());
 
   prescient_networking_dispatcher_.reset(