[MediaRouter] Update MR-2-Extension's PostMessage to return boolean.

chrome/browser/media/router/media_router_mojo_impl_unittest.cc

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <string>
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/run_loop.h"
@@ skipping 255 matching lines @@
 
   EXPECT_CALL(mock_router, UnregisterMediaRoutesObserver(&routes_observer));
   EXPECT_CALL(mock_router,
               UnregisterMediaRoutesObserver(&extra_routes_observer));
   router()->UnregisterMediaRoutesObserver(&routes_observer);
   router()->UnregisterMediaRoutesObserver(&extra_routes_observer);
   EXPECT_CALL(mock_mojo_media_router_service_, StopObservingMediaRoutes());
   ProcessEventLoop();
 }
 
+void AssertPostMessageResult(bool expected, bool actual) {
+  EXPECT_EQ(expected, actual);
+}
+
 TEST_F(MediaRouterMojoImplTest, PostMessage) {
   EXPECT_CALL(mock_mojo_media_router_service_,
-              PostMessage(mojo::String(kRouteId), mojo::String(kMessage)));
-  router()->PostMessage(kRouteId, kMessage);
+              PostMessage(mojo::String(kRouteId), mojo::String(kMessage), _))
+      .WillOnce(
+          Invoke([](const MediaRoute::Id& route_id, const std::string& message,
+                    const interfaces::MediaRouter::PostMessageCallback& cb) {
+            cb.Run(true);
+          }));
+
+  router()->PostMessage(kRouteId, kMessage,
+                        base::Bind(&AssertPostMessageResult, true));
   ProcessEventLoop();
 }
 
 TEST_F(MediaRouterMojoImplTest, QueuedWhileAsleep) {
   EXPECT_CALL(mock_event_page_tracker_, IsEventPageSuspended(extension_id()))
       .Times(2)
       .WillRepeatedly(Return(true));
   EXPECT_CALL(mock_event_page_tracker_, WakeEventPage(extension_id(), _))
       .Times(2)
       .WillRepeatedly(Return(true));
@@ skipping 81 matching lines @@
               CloseRoute(mojo::String(kRouteId2)));
   binding.reset(new mojo::Binding<interfaces::MediaRouter>(
       &mock_mojo_media_router_service, mojo::GetProxy(&mojo_media_router)));
   mojo_media_router_observer->ProvideMediaRouter(
       mojo_media_router.Pass(), base::Bind(&ProvideMediaRouterHandler::Invoke,
                                            base::Unretained(&provide_handler)));
   message_loop.RunUntilIdle();
 }
 
 }  // namespace media_router