Extract LazyBackgroundTaskQueue from ExtensionSystem.

extensions/browser/mock_extension_system.h

 // Copyright 2014 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_MOCK_EXTENSION_SYSTEM_H_
 #define EXTENSIONS_BROWSER_MOCK_EXTENSION_SYSTEM_H_
 
 #include "components/keyed_service/content/browser_context_dependency_manager.h"
 #include "extensions/browser/extension_registry_factory.h"
 #include "extensions/browser/extension_system.h"
@@ skipping 19 matching lines @@
   // ExtensionSystem overrides:
   void InitForRegularProfile(bool extensions_enabled) override;
   ExtensionService* extension_service() override;
   RuntimeData* runtime_data() override;
   ManagementPolicy* management_policy() override;
   SharedUserScriptMaster* shared_user_script_master() override;
   DeclarativeUserScriptManager* declarative_user_script_manager() override;
   StateStore* state_store() override;
   StateStore* rules_store() override;
   InfoMap* info_map() override;
-  LazyBackgroundTaskQueue* lazy_background_task_queue() override;
   EventRouter* event_router() override;
   InstallVerifier* install_verifier() override;
   QuotaService* quota_service() override;
   const OneShotEvent& ready() const override;
   ContentVerifier* content_verifier() override;
   scoped_ptr<ExtensionSet> GetDependentExtensions(
       const Extension* extension) override;
 
  private:
   content::BrowserContext* browser_context_;
@@ skipping 34 matching lines @@
         GetServiceForBrowserContext(context, true));
   }
 
  private:
   DISALLOW_COPY_AND_ASSIGN(MockExtensionSystemFactory);
 };
 
 }  // namespace extensions
 
 #endif  // EXTENSIONS_BROWSER_MOCK_EXTENSION_SYSTEM_H_