[Media Router] Adds return value to mojo MediaRouteProvider::TerminateRoute.

chrome/browser/media/router/mojo/media_router_mojo_impl.h

Index: chrome/browser/media/router/mojo/media_router_mojo_impl.h
diff --git a/chrome/browser/media/router/mojo/media_router_mojo_impl.h b/chrome/browser/media/router/mojo/media_router_mojo_impl.h
index 44fdb4674e984be5f30ada589afc6860ac43ca29..7060dd0417e47dca9dd4ef3c31e90e9273ea8b2f 100644
--- a/chrome/browser/media/router/mojo/media_router_mojo_impl.h
+++ b/chrome/browser/media/router/mojo/media_router_mojo_impl.h
@@ -305,6 +305,12 @@ class MediaRouterMojoImpl : public MediaRouterBase,
       const mojo::String& route_id,
       mojo::Array<interfaces::RouteMessagePtr> messages) override;
 
+  // Result callback when Mojo terminateRoute is invoked.  |route_id| is bound
+  // to the ID of the route that was terminated.
+  void OnTerminateRouteResult(const MediaRoute::Id& route_id,
+                              mojo::String error_text,
+                              interfaces::RouteRequestResultCode result_code);
+
   // Converts the callback result of calling Mojo CreateRoute()/JoinRoute()
   // into a local callback.
   void RouteResponseReceived(