[GCM] Observe the event listener adding such that GCM can be started

chrome/browser/services/gcm/gcm_profile_service_unittest.cc

 // Copyright (c) 2013 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 <algorithm>
 #include <map>
 
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/message_loop/message_loop.h"
@@ skipping 11 matching lines @@
 #include "chrome/browser/signin/signin_manager_base.h"
 #include "chrome/browser/signin/signin_manager_factory.h"
 #include "chrome/browser/ui/browser.h"
 #include "chrome/common/extensions/features/feature_channel.h"
 #include "chrome/common/pref_names.h"
 #include "chrome/test/base/testing_profile.h"
 #include "components/encryptor/os_crypt.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/notification_service.h"
 #include "content/public/test/test_browser_thread_bundle.h"
+#include "extensions/browser/event_router.h"
+#include "extensions/browser/extension_prefs.h"
 #include "extensions/common/extension.h"
 #include "extensions/common/manifest_constants.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 #if defined(OS_CHROMEOS)
 #include "chrome/browser/chromeos/login/user_manager.h"
 #include "chrome/browser/chromeos/settings/cros_settings.h"
 #include "chrome/browser/chromeos/settings/device_settings_service.h"
 #endif
 
@@ skipping 234 matching lines @@
             profile(), &GCMProfileServiceTestConsumer::BuildFakeSigninManager));
 
     // Create extension service in order to uninstall the extension.
     extensions::TestExtensionSystem* extension_system(
         static_cast<extensions::TestExtensionSystem*>(
             extensions::ExtensionSystem::Get(profile())));
     extension_system->CreateExtensionService(
         CommandLine::ForCurrentProcess(), base::FilePath(), false);
     extension_service_ = extension_system->Get(profile())->extension_service();
 
+    // EventRouter is needed for GcmJsEventRouter.
+    if (!extension_system->event_router()) {
+      extension_system->SetEventRouter(scoped_ptr<EventRouter>(
+          new EventRouter(profile(), ExtensionPrefs::Get(profile()))));
+    }
+
     // Enable GCM such that tests could be run on all channels.
     profile()->GetPrefs()->SetBoolean(prefs::kGCMChannelEnabled, true);
 
     // Mock a GCMEventRouter.
     gcm_event_router_.reset(new FakeGCMEventRouter(waiter_));
   }
 
   virtual ~GCMProfileServiceTestConsumer() {
   }
 
@@ skipping 1122 matching lines @@
   consumer()->gcm_event_router()->clear_results();
   WaitUntilCompleted();
 
   EXPECT_EQ(FakeGCMEventRouter::MESSAGE_EVENT,
             consumer()->gcm_event_router()->received_event());
   EXPECT_TRUE(
       in_message5.data == consumer()->gcm_event_router()->message().data);
 }
 
 }  // namespace gcm