Move Extension into extensions namespace

chrome/browser/ui/tabs/tab_strip_model_unittest.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/ui/tabs/tab_strip_model.h"
 
 #include <map>
 #include <string>
 
 #include "base/file_path.h"
@@ skipping 28 matching lines @@
 #include "content/public/browser/render_process_host.h"
 #include "content/public/browser/web_contents.h"
 #include "content/test/notification_observer_mock.h"
 #include "content/test/test_browser_thread.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 using content::BrowserThread;
 using content::NavigationController;
 using content::SiteInstance;
 using content::WebContents;
+using extensions::Extension;
 using testing::_;
 
 namespace {
 
 // Class used to delete a TabContentsWrapper when another TabContentsWrapper is
 // destroyed.
 class DeleteTabContentsOnDestroyedObserver
     : public content::NotificationObserver {
  public:
   DeleteTabContentsOnDestroyedObserver(TabContentsWrapper* source,
@@ skipping 2381 matching lines @@
   ASSERT_EQ(1, observer.GetStateCount());
   MockTabStripModelObserver::State s(
       contents2, 1, MockTabStripModelObserver::SELECT);
   s.src_contents = contents2;
   s.src_index = 1;
   s.user_gesture = false;
   EXPECT_TRUE(observer.StateEquals(0, s));
   strip.RemoveObserver(&observer);
   strip.CloseAllTabs();
 }