Fix memory leak caused by Rules Registries

chrome/browser/extensions/api/declarative/rules_registry_service.h

Index: chrome/browser/extensions/api/declarative/rules_registry_service.h
diff --git a/chrome/browser/extensions/api/declarative/rules_registry_service.h b/chrome/browser/extensions/api/declarative/rules_registry_service.h
index 92bb166f75bc5fa4ac7b7a8ad85c97d72976a3b8..c0150512fc91c0e081047720e57370774971326f 100644
--- a/chrome/browser/extensions/api/declarative/rules_registry_service.h
+++ b/chrome/browser/extensions/api/declarative/rules_registry_service.h
@@ -34,6 +34,10 @@ class RulesRegistryService : public content::NotificationObserver  {
   explicit RulesRegistryService(Profile* profile);
   virtual ~RulesRegistryService();
 
+  // Unregisters refptrs to concrete RulesRegistries at other objects that were
+  // created by us so that the RulesRegistries can be released.
+  void Shutdown();
+
   // Registers the default RulesRegistries used in Chromium.
   void RegisterDefaultRulesRegistries();