Split ExtensionTestObserver and move to //extensions.

chrome/browser/extensions/extension_crash_recovery_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 <stddef.h>
 
 #include "base/run_loop.h"
 #include "build/build_config.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/extensions/extension_browsertest.h"
 #include "chrome/browser/extensions/extension_service.h"
 #include "chrome/browser/notifications/notification.h"
 #include "chrome/browser/notifications/notification_delegate.h"
 #include "chrome/browser/notifications/notification_ui_manager.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/ui/browser.h"
 #include "chrome/browser/ui/browser_commands.h"
 #include "chrome/browser/ui/tabs/tab_strip_model.h"
 #include "chrome/test/base/ui_test_utils.h"
 #include "content/public/browser/navigation_controller.h"
+#include "content/public/browser/notification_types.h"
 #include "content/public/browser/render_process_host.h"
 #include "content/public/browser/render_view_host.h"
 #include "content/public/browser/web_contents.h"
 #include "content/public/common/result_codes.h"
 #include "content/public/common/url_constants.h"
 #include "extensions/browser/extension_host.h"
 #include "extensions/browser/extension_registry.h"
 #include "extensions/browser/extension_system.h"
 #include "extensions/browser/process_manager.h"
 #include "extensions/browser/process_map.h"
@@ skipping 525 matching lines @@
                 GetController()));
     chrome::Reload(browser(), WindowOpenDisposition::CURRENT_TAB);
     observer.Wait();
   }
   // Extension should now be loaded.
   SCOPED_TRACE("after reloading the tab");
   CheckExtensionConsistency(first_extension_id_);
   ASSERT_EQ(count_before + 1, GetEnabledExtensionCount());
   ASSERT_EQ(0U, CountBalloons());
 }