Add a test helper class for ExtensionRegistry.

chrome/browser/extensions/extension_storage_monitor_browsertest.cc

 // Copyright 2014 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 <set>
 
 #include "base/run_loop.h"
 #include "base/strings/string_number_conversions.h"
 #include "chrome/browser/extensions/extension_browsertest.h"
 #include "chrome/browser/extensions/extension_service.h"
 #include "chrome/browser/extensions/extension_storage_monitor.h"
 #include "chrome/browser/extensions/extension_test_message_listener.h"
 #include "chrome/browser/ui/extensions/application_launch.h"
 #include "content/public/test/test_utils.h"
 #include "extensions/browser/extension_prefs.h"
+#include "extensions/browser/extension_registry.h"
 #include "extensions/browser/extension_system.h"
+#include "extensions/browser/test_extension_registry_observer.h"
 #include "ui/message_center/message_center.h"
 #include "ui/message_center/message_center_observer.h"
 
 namespace extensions {
 
 namespace {
 
 const int kInitialUsageThreshold = 500;
 
 const char kWriteDataApp[] = "storage_monitor/write_data";
@@ skipping 298 matching lines @@
   const Extension* extension = InitWriteDataApp();
   ASSERT_TRUE(extension);
   WriteBytesExpectingNotification(extension, GetInitialExtensionThreshold());
 
   // Fake clicking the notification button to uninstall.
   message_center::MessageCenter::Get()->ClickOnNotificationButton(
       GetNotificationId(extension->id()),
       ExtensionStorageMonitor::BUTTON_UNINSTALL);
 
   // Also fake accepting the uninstall.
-  content::WindowedNotificationObserver uninstalled_signal(
-      chrome::NOTIFICATION_EXTENSION_UNINSTALLED_DEPRECATED,
-      content::Source<Profile>(profile()));
+  TestExtensionRegistryObserver observer(ExtensionRegistry::Get(profile()),
+                                         extension->id());
   SimulateUninstallDialogAccept();
-  uninstalled_signal.Wait();
+  observer.WaitForExtensionUninstalled();
 }
 
 }  // namespace extensions