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

extensions/browser/extension_prefs_factory.cc

Index: extensions/browser/extension_prefs_factory.cc
diff --git a/extensions/browser/extension_prefs_factory.cc b/extensions/browser/extension_prefs_factory.cc
index c07229cb7da1629da4ff7a7f62b127beb545aff6..9e1d3ec5ba7e44d2ba506919078eb73cfbe0e073 100644
--- a/extensions/browser/extension_prefs_factory.cc
+++ b/extensions/browser/extension_prefs_factory.cc
@@ -28,8 +28,9 @@ ExtensionPrefsFactory* ExtensionPrefsFactory::GetInstance() {
 }
 
 void ExtensionPrefsFactory::SetInstanceForTesting(
-    content::BrowserContext* context, ExtensionPrefs* prefs) {
-  Associate(context, prefs);
+    content::BrowserContext* context,
+    scoped_ptr<ExtensionPrefs> prefs) {
+  Associate(context, prefs.Pass());
 }
 
 ExtensionPrefsFactory::ExtensionPrefsFactory()