Extract LazyBackgroundTaskQueue from ExtensionSystem.

extensions/browser/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_EXTENSION_SYSTEM_H_
 #define EXTENSIONS_BROWSER_EXTENSION_SYSTEM_H_
 
 #include <string>
 
 #include "base/memory/ref_counted.h"
@@ skipping 18 matching lines @@
 
 namespace extensions {
 
 class ContentVerifier;
 class DeclarativeUserScriptManager;
 class EventRouter;
 class Extension;
 class ExtensionSet;
 class InfoMap;
 class InstallVerifier;
-class LazyBackgroundTaskQueue;
 class ManagementPolicy;
 class OneShotEvent;
 class QuotaService;
 class RuntimeData;
 class SharedUserScriptMaster;
 class StateStore;
 
 // ExtensionSystem manages the lifetime of many of the services used by the
 // extensions and apps system, and it handles startup and shutdown as needed.
 // Eventually, we'd like to make more of these services into KeyedServices in
@@ skipping 31 matching lines @@
 
   // The StateStore is created at startup.
   virtual StateStore* state_store() = 0;
 
   // The rules store is created at startup.
   virtual StateStore* rules_store() = 0;
 
   // Returns the IO-thread-accessible extension data.
   virtual InfoMap* info_map() = 0;
 
-  // The LazyBackgroundTaskQueue is created at startup.
-  virtual LazyBackgroundTaskQueue* lazy_background_task_queue() = 0;
-
   // The EventRouter is created at startup.
   virtual EventRouter* event_router() = 0;
 
   // The InstallVerifier is created at startup.
   virtual InstallVerifier* install_verifier() = 0;
 
   // Returns the QuotaService that limits calls to certain extension functions.
   // Lives on the UI thread. Created at startup.
   virtual QuotaService* quota_service() = 0;
 
@@ skipping 21 matching lines @@
   // Get a set of extensions that depend on the given extension.
   // TODO(elijahtaylor): Move SharedModuleService out of chrome/browser
   // so it can be retrieved from ExtensionSystem directly.
   virtual scoped_ptr<ExtensionSet> GetDependentExtensions(
       const Extension* extension) = 0;
 };
 
 }  // namespace extensions
 
 #endif  // EXTENSIONS_BROWSER_EXTENSION_SYSTEM_H_