Show Media Router toolbar icon ephemerally for MR dialogs

chrome/test/BUILD.gn

Index: chrome/test/BUILD.gn
diff --git a/chrome/test/BUILD.gn b/chrome/test/BUILD.gn
index a2890a67ab0888b4350388b1ba629c96906e71d8..057496d0e2942d4ac29b833bb794a501253d8a6b 100644
--- a/chrome/test/BUILD.gn
+++ b/chrome/test/BUILD.gn
@@ -4310,9 +4310,9 @@ test("unit_tests") {
         "../browser/ui/webui/media_router/cast_modes_with_media_sources_unittest.cc",
         "../browser/ui/webui/media_router/media_cast_mode_unittest.cc",
         "../browser/ui/webui/media_router/media_router_dialog_controller_impl_unittest.cc",
-        "../browser/ui/webui/media_router/media_router_test.cc",
-        "../browser/ui/webui/media_router/media_router_test.h",
         "../browser/ui/webui/media_router/media_router_ui_unittest.cc",
+        "../browser/ui/webui/media_router/media_router_web_ui_test.cc",
+        "../browser/ui/webui/media_router/media_router_web_ui_test.h",
         "../browser/ui/webui/media_router/media_router_webui_message_handler_unittest.cc",
         "../browser/ui/webui/media_router/query_result_manager_unittest.cc",
       ]