[Cleanup] Used scoped pointers in KeyedServiceFactory's SetTestingFactory functions.

extensions/browser/api/storage/storage_frontend.h

Index: extensions/browser/api/storage/storage_frontend.h
diff --git a/extensions/browser/api/storage/storage_frontend.h b/extensions/browser/api/storage/storage_frontend.h
index 5e11b82524e8490ec420a3ca9de66d158ba89da6..f1c82874479b5ec0a3fe81dc637a34d21492baa7 100644
--- a/extensions/browser/api/storage/storage_frontend.h
+++ b/extensions/browser/api/storage/storage_frontend.h
@@ -28,8 +28,8 @@ class StorageFrontend : public BrowserContextKeyedAPI {
   // Returns the current instance for |context|.
   static StorageFrontend* Get(content::BrowserContext* context);
 
-  // Creates with a specific |storage_factory|. Caller owns the object.
-  static StorageFrontend* CreateForTesting(
+  // Creates with a specific |storage_factory|.
+  static scoped_ptr<StorageFrontend> CreateForTesting(
       const scoped_refptr<SettingsStorageFactory>& storage_factory,
       content::BrowserContext* context);