[Media Router] Notify MRUI of a media status update when it starts observing

chrome/browser/ui/webui/media_router/media_router_ui.cc

Index: chrome/browser/ui/webui/media_router/media_router_ui.cc
diff --git a/chrome/browser/ui/webui/media_router/media_router_ui.cc b/chrome/browser/ui/webui/media_router/media_router_ui.cc
index 924e26a94dfd80d50b5f08d7887e5bc0983e8be5..0b58cfb34ac9f1cdabee3b2a0c9ba2bf5b43800f 100644
--- a/chrome/browser/ui/webui/media_router/media_router_ui.cc
+++ b/chrome/browser/ui/webui/media_router/media_router_ui.cc
@@ -157,7 +157,11 @@ void MediaRouterUI::UIMediaRoutesObserver::OnRoutesUpdated(
 MediaRouterUI::UIMediaRouteControllerObserver::UIMediaRouteControllerObserver(
     MediaRouterUI* ui,
     scoped_refptr<MediaRouteController> controller)
-    : MediaRouteController::Observer(std::move(controller)), ui_(ui) {}
+    : MediaRouteController::Observer(std::move(controller)), ui_(ui) {
+  if (controller_->current_media_status())
+    OnMediaStatusUpdated(controller_->current_media_status().value());
+}
+
 MediaRouterUI::UIMediaRouteControllerObserver::
     ~UIMediaRouteControllerObserver() {}