Split ExtensionTestObserver and move to //extensions.

chrome/browser/extensions/activity_log/activity_log_browsertest.cc

 // Copyright (c) 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 <stdint.h>
 
 #include "base/callback.h"
 #include "base/location.h"
 #include "base/run_loop.h"
 #include "base/single_thread_task_runner.h"
 #include "base/strings/stringprintf.h"
 #include "chrome/browser/extensions/activity_log/activity_log.h"
 #include "chrome/browser/extensions/extension_apitest.h"
 #include "chrome/browser/extensions/extension_browsertest.h"
 #include "chrome/browser/prerender/prerender_handle.h"
 #include "chrome/browser/prerender/prerender_manager.h"
 #include "chrome/browser/prerender/prerender_manager_factory.h"
 #include "chrome/browser/ui/tabs/tab_strip_model.h"
 #include "chrome/common/chrome_switches.h"
 #include "content/public/browser/notification_service.h"
+#include "content/public/browser/notification_types.h"
 #include "content/public/test/browser_test_utils.h"
 #include "content/public/test/test_utils.h"
 #include "net/dns/mock_host_resolver.h"
 #include "net/test/embedded_test_server/embedded_test_server.h"
 
 namespace extensions {
 
 // Only the prerender tests are in this file. To add tests for activity
 // logging please see:
 //    chrome/test/data/extensions/api_test/activity_log_private/README
@@ skipping 84 matching lines @@
   activity_log->GetFilteredActions(
       ext->id(), Action::ACTION_ANY, "", "", "", -1,
       base::Bind(ActivityLogPrerenderTest::Prerender_Arguments, ext->id(), port,
                  run_loop.QuitWhenIdleClosure()));
 
   // Allow invocation of Prerender_Arguments
   run_loop.Run();
 }
 
 }  // namespace extensions