Add a test helper class for ExtensionRegistry.

chrome/browser/extensions/api/enterprise_platform_keys/enterprise_platform_keys_apitest_nss.cc

Index: chrome/browser/extensions/api/enterprise_platform_keys/enterprise_platform_keys_apitest_nss.cc
diff --git a/chrome/browser/extensions/api/enterprise_platform_keys/enterprise_platform_keys_apitest_nss.cc b/chrome/browser/extensions/api/enterprise_platform_keys/enterprise_platform_keys_apitest_nss.cc
index d37b977d1f1e8051e8c8d53104bf6c8bc48a1b80..b42b1b7d7aace34c405be9dec40afbe71504a927 100644
--- a/chrome/browser/extensions/api/enterprise_platform_keys/enterprise_platform_keys_apitest_nss.cc
+++ b/chrome/browser/extensions/api/enterprise_platform_keys/enterprise_platform_keys_apitest_nss.cc
@@ -20,6 +20,8 @@
 #include "content/public/test/test_utils.h"
 #include "content/test/net/url_request_mock_http_job.h"
 #include "crypto/nss_util.h"
+#include "extensions/browser/extension_registry.h"
+#include "extensions/browser/test_extension_registry_observer.h"
 #include "net/base/net_errors.h"
 #include "net/cert/nss_cert_database.h"
 #include "policy/policy_constants.h"
@@ -201,11 +203,10 @@ class EnterprisePlatformKeysTest : public ExtensionApiTest {
                NULL);
 
     // Set the policy and wait until the extension is installed.
-    content::WindowedNotificationObserver observer(
-        chrome::NOTIFICATION_EXTENSION_INSTALLED_DEPRECATED,
-        content::NotificationService::AllSources());
+    extensions::ExtensionTestRegistryObserver observer(
+        extensions::ExtensionRegistry::Get(browser()->profile()));
     policy_provider_.UpdateChromePolicy(policy);
-    observer.Wait();
+    observer.WaitForAnyExtensionWillBeInstalled();
   }
 
   scoped_ptr<crypto::ScopedTestNSSDB> test_nssdb_;