Allow MediaSession in iframes to be routed

content/browser/media/session/media_session_controller.cc

Index: content/browser/media/session/media_session_controller.cc
diff --git a/content/browser/media/session/media_session_controller.cc b/content/browser/media/session/media_session_controller.cc
index 970bb4cb738f344d13d337684a78f08dae89d254..4870db244339242dd9800ee2ff46b793d6c3e244 100644
--- a/content/browser/media/session/media_session_controller.cc
+++ b/content/browser/media/session/media_session_controller.cc
@@ -95,6 +95,10 @@ void MediaSessionController::OnSetVolumeMultiplier(int player_id,
           id_.first->GetRoutingID(), id_.second, volume_multiplier));
 }
 
+RenderFrameHost* MediaSessionController::GetRenderFrameHost() const {
+  return id_.first;
+}
+
 void MediaSessionController::OnPlaybackPaused() {
   // We check for suspension here since the renderer may issue its own pause
   // in response to or while a pause from the browser is in flight.