[Extensions] Move [Chrome]ExtensionTestNotificationObserver into extensions::

chrome/browser/chromeos/first_run/drive_first_run_browsertest.cc

 // Copyright 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 <memory>
 
 #include "base/bind.h"
 #include "base/files/file_path.h"
 #include "base/message_loop/message_loop.h"
 #include "base/path_service.h"
@@ skipping 111 matching lines @@
   controller_->SetAppInfoForTest(kTestAppId, endpoint_url_);
 }
 
 void DriveFirstRunTest::InstallApp() {
   ExtensionService* extension_service = extensions::ExtensionSystem::Get(
       browser()->profile())->extension_service();
   scoped_refptr<extensions::CrxInstaller> installer =
       extensions::CrxInstaller::CreateSilent(extension_service);
 
   installer->InstallCrx(test_data_dir_.AppendASCII(kTestAppCrxName));
-  ChromeExtensionTestNotificationObserver observer(browser());
+  extensions::ChromeExtensionTestNotificationObserver observer(browser());
   observer.WaitForExtensionLoad();
 
   ASSERT_TRUE(extension_service->GetExtensionById(kTestAppId, false));
 }
 
 void DriveFirstRunTest::EnableOfflineMode() {
   controller_->EnableOfflineMode();
 }
 
 void DriveFirstRunTest::SetDelays(int initial_delay_secs, int timeout_secs) {
@@ skipping 41 matching lines @@
   // Test that the controller times out instead of hanging forever.
   InstallApp();
   InitTestServer(kBadServerDirectory);
   SetDelays(0, 0);
   EnableOfflineMode();
   EXPECT_FALSE(WaitForFirstRunResult());
   EXPECT_TRUE(timed_out());
 }
 
 }  // namespace chromeos