Add a test helper class for ExtensionRegistry.

chrome/browser/extensions/extension_storage_monitor_browsertest.cc

Index: chrome/browser/extensions/extension_storage_monitor_browsertest.cc
diff --git a/chrome/browser/extensions/extension_storage_monitor_browsertest.cc b/chrome/browser/extensions/extension_storage_monitor_browsertest.cc
index 1c32600bdcaf19a3d5397821ca240bddb11604e1..a3e0e17f92aed247f469f5b1d2be80817c7a9a3e 100644
--- a/chrome/browser/extensions/extension_storage_monitor_browsertest.cc
+++ b/chrome/browser/extensions/extension_storage_monitor_browsertest.cc
@@ -13,7 +13,9 @@
 #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"
 
@@ -332,11 +334,10 @@ IN_PROC_BROWSER_TEST_F(ExtensionStorageMonitorTest, UninstallExtension) {
       ExtensionStorageMonitor::BUTTON_UNINSTALL);
 
   // Also fake accepting the uninstall.
-  content::WindowedNotificationObserver uninstalled_signal(
-      chrome::NOTIFICATION_EXTENSION_UNINSTALLED_DEPRECATED,
-      content::Source<Profile>(profile()));
+  extensions::TestExtensionRegistryObserver observer(
+      extensions::ExtensionRegistry::Get(profile()));
   SimulateUninstallDialogAccept();
-  uninstalled_signal.Wait();
+  observer.WaitForExtensionUninstalled(extension->id());

[Yoyo Zhou, 2014/06/17 18:15:37]

You should copy extension->id() into a temporary string because if the extension
is uninstalled, extension can become invalid.

[limasdf, 2014/06/19 18:06:28]

Pass to the contructor.

 }
 
 }  // namespace extensions