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

chrome/browser/extensions/extension_browsertest.cc

 // Copyright (c) 2012 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 "chrome/browser/extensions/extension_browsertest.h"
 
 #include <stddef.h>
 
 #include <utility>
 #include <vector>
@@ skipping 129 matching lines @@
     // running on chromeos.
     command_line->AppendSwitchASCII(chromeos::switches::kLoginUser,
                                     "testuser@gmail.com");
     command_line->AppendSwitchASCII(chromeos::switches::kLoginProfile, "user");
   }
 #endif
 }
 
 void ExtensionBrowserTest::SetUpOnMainThread() {
   InProcessBrowserTest::SetUpOnMainThread();
-  observer_.reset(new ChromeExtensionTestNotificationObserver(browser()));
+  observer_.reset(
+      new extensions::ChromeExtensionTestNotificationObserver(browser()));
   if (extension_service()->updater()) {
     extension_service()->updater()->SetExtensionCacheForTesting(
         test_extension_cache_.get());
   }
 }
 
 void ExtensionBrowserTest::TearDownOnMainThread() {
   ExtensionMessageBubbleFactory::set_override_for_tests(
       ExtensionMessageBubbleFactory::NO_OVERRIDE);
   InProcessBrowserTest::TearDownOnMainThread();
@@ skipping 389 matching lines @@
   return extensions::browsertest_util::ExecuteScriptInBackgroundPage(
       profile(), extension_id, script);
 }
 
 bool ExtensionBrowserTest::ExecuteScriptInBackgroundPageNoWait(
     const std::string& extension_id,
     const std::string& script) {
   return extensions::browsertest_util::ExecuteScriptInBackgroundPageNoWait(
       profile(), extension_id, script);
 }