MediaRouterAction: Only observe Media Routes when there is a local route.

chrome/browser/media/android/router/media_router_android.cc

Index: chrome/browser/media/android/router/media_router_android.cc
diff --git a/chrome/browser/media/android/router/media_router_android.cc b/chrome/browser/media/android/router/media_router_android.cc
index dd7a52721e3a663769d52a43cdcf974fa2c27593..62206e09f85576acf76e5312f1d789209cf288b4 100644
--- a/chrome/browser/media/android/router/media_router_android.cc
+++ b/chrome/browser/media/android/router/media_router_android.cc
@@ -188,6 +188,11 @@ void MediaRouterAndroid::OnPresentationSessionDetached(
   CloseRoute(route_id);
 }
 
+bool MediaRouterAndroid::HasLocalRoute() const {
+  NOTIMPLEMENTED();
+  return false;
+}
+
 bool MediaRouterAndroid::RegisterMediaSinksObserver(
     MediaSinksObserver* observer) {
   const std::string& source_id = observer->source().id();
@@ -276,6 +281,16 @@ void MediaRouterAndroid::UnregisterPresentationSessionMessagesObserver(
     messages_observers_.erase(route_id);
 }
 
+void MediaRouterAndroid::RegisterLocalMediaRoutesObserver(
+    LocalMediaRoutesObserver* observer) {
+  NOTIMPLEMENTED();
+}
+
+void MediaRouterAndroid::UnregisterLocalMediaRoutesObserver(
+    LocalMediaRoutesObserver* observer) {
+  NOTIMPLEMENTED();
+}
+
 void MediaRouterAndroid::OnSinksReceived(
     JNIEnv* env,
     jobject obj,