This patch improves the way that GuestViewManager tracks the destruction of GuestView embedders.

extensions/browser/api/declarative/rules_registry_service.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef EXTENSIONS_BROWSER_API_DECLARATIVE_RULES_REGISTRY_SERVICE_H__
 #define EXTENSIONS_BROWSER_API_DECLARATIVE_RULES_REGISTRY_SERVICE_H__
 
 #include <map>
 #include <string>
 #include <vector>
@@ skipping 43 matching lines @@
   ~RulesRegistryService() override;
 
   // Unregisters refptrs to concrete RulesRegistries at other objects that were
   // created by us so that the RulesRegistries can be released.
   void Shutdown() override;
 
   // BrowserContextKeyedAPI implementation.
   static BrowserContextKeyedAPIFactory<RulesRegistryService>*
       GetFactoryInstance();
 
-  // Convenience method to get the RulesRegistryService for a context.
+  // Convenience method to get the RulesRegistryService for a context. If
+  // |create| is provided, it specifies whether a new RulesRegistryService
+  // should be created if one does not already exist (true if omitted). If
+  // |create| is false and one does not already exist, nullptr will be returned.
   static RulesRegistryService* Get(content::BrowserContext* context);
+  static RulesRegistryService* Get(content::BrowserContext* context,
+                                   bool create);
 
   int GetNextRulesRegistryID();
 
   // Registers the default RulesRegistries used in Chromium.
   void EnsureDefaultRulesRegistriesRegistered(int rules_registry_id);
 
   // Registers a RulesRegistry and wraps it in an InitializingRulesRegistry.
   void RegisterRulesRegistry(scoped_refptr<RulesRegistry> rule_registry);
 
   // Returns the RulesRegistry for |event_name| and |rules_registry_id| or
@@ skipping 63 matching lines @@
       extension_registry_observer_;
 
   content::BrowserContext* browser_context_;
 
   DISALLOW_COPY_AND_ASSIGN(RulesRegistryService);
 };
 
 }  // namespace extensions
 
 #endif  // EXTENSIONS_BROWSER_API_DECLARATIVE_RULES_REGISTRY_SERVICE_H__