[Media Router] Implement an internal Media Routes observer.

chrome/browser/media/router/mojo/media_router_mojo_test.cc

Index: chrome/browser/media/router/mojo/media_router_mojo_test.cc
diff --git a/chrome/browser/media/router/mojo/media_router_mojo_test.cc b/chrome/browser/media/router/mojo/media_router_mojo_test.cc
index 4506639f7460baaf8283647cd9b712c5b45833bf..60fcdf4cd6fc295176b5a8c25e6ba9af0da75c87 100644
--- a/chrome/browser/media/router/mojo/media_router_mojo_test.cc
+++ b/chrome/browser/media/router/mojo/media_router_mojo_test.cc
@@ -32,6 +32,7 @@ MockEventPageTracker::~MockEventPageTracker() {}
 
 MediaRouterMojoTest::MediaRouterMojoTest()
     : mock_media_router_(new MediaRouterMojoImpl(&mock_event_page_tracker_)) {
+  mock_media_router_->Initialize();
   mock_media_router_->set_instance_id_for_test(kInstanceId);
   extension_ = extensions::test_util::CreateEmptyExtension();
 }
@@ -61,6 +62,10 @@ void MediaRouterMojoTest::SetUp() {
   base::RunLoop().RunUntilIdle();
 }
 
+void MediaRouterMojoTest::TearDown() {
+  mock_media_router_->Shutdown();
+}
+
 void MediaRouterMojoTest::ProcessEventLoop() {
   base::RunLoop().RunUntilIdle();
 }