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

chrome/browser/ui/webui/extensions/extension_settings_browsertest.h

 // 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.
 
 #ifndef CHROME_BROWSER_UI_WEBUI_EXTENSIONS_EXTENSION_SETTINGS_BROWSERTEST_H_
 #define CHROME_BROWSER_UI_WEBUI_EXTENSIONS_EXTENSION_SETTINGS_BROWSERTEST_H_
 
 #include "base/macros.h"
 #include "chrome/browser/extensions/chrome_extension_test_notification_observer.h"
 #include "chrome/test/base/web_ui_browser_test.h"
@@ skipping 42 matching lines @@
 
   // Shrinks the web contents view in order to ensure vertical overflow.
   void ShrinkWebContentsView();
 
  private:
   bool WaitForExtensionViewsToLoad();
   const extensions::Extension* InstallUnpackedExtension(
       const base::FilePath& path);
   const extensions::Extension* InstallExtension(const base::FilePath& path);
 
-  std::unique_ptr<ChromeExtensionTestNotificationObserver> observer_;
+  std::unique_ptr<extensions::ChromeExtensionTestNotificationObserver>
+      observer_;
 
   // The default profile to be used.
   Profile* profile_;
 
   // Used to simulate managed extensions (by being registered as a provider).
   extensions::TestManagementPolicyProvider policy_provider_;
 
   base::FilePath test_data_dir_;
 
   // Used to enable the error console.
   std::unique_ptr<extensions::FeatureSwitch::ScopedOverride>
       error_console_override_;
 
   std::unique_ptr<extensions::ScopedTestDialogAutoConfirm>
       uninstall_auto_confirm_;
 
   DISALLOW_COPY_AND_ASSIGN(ExtensionSettingsUIBrowserTest);
 };
 
 #endif  // CHROME_BROWSER_UI_WEBUI_EXTENSIONS_EXTENSION_SETTINGS_BROWSERTEST_H_