Remove DeferBackgroundExtensionCreation field trial and supporting code

chrome/browser/extensions/test_extension_system.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 CHROME_BROWSER_EXTENSIONS_TEST_EXTENSION_SYSTEM_H_
 #define CHROME_BROWSER_EXTENSIONS_TEST_EXTENSION_SYSTEM_H_
 
 #include "chrome/browser/extensions/extension_system.h"
 
 class CommandLine;
@@ skipping 35 matching lines @@
 
   // Creates a ProcessManager. If not invoked, the ProcessManager is NULL.
   void CreateProcessManager();
 
   // Allows the ProcessManager to be overriden, for example by a stub
   // implementation. Takes ownership of |manager|.
   void SetProcessManager(ProcessManager* manager);
 
   void CreateSocketManager();
 
-  virtual void InitForRegularProfile(bool extensions_enabled,
-                                     bool defer_background_creation) OVERRIDE {}
+  virtual void InitForRegularProfile(bool extensions_enabled) OVERRIDE {}
   void SetExtensionService(ExtensionService* service);
   virtual ExtensionService* extension_service() OVERRIDE;
   virtual ManagementPolicy* management_policy() OVERRIDE;
   virtual UserScriptMaster* user_script_master() OVERRIDE;
   virtual ProcessManager* process_manager() OVERRIDE;
   virtual StateStore* state_store() OVERRIDE;
   virtual StateStore* rules_store() OVERRIDE;
   TestingValueStore* value_store() { return value_store_; }
   virtual InfoMap* info_map() OVERRIDE;
   virtual LazyBackgroundTaskQueue* lazy_background_task_queue() OVERRIDE;
@@ skipping 27 matching lines @@
   scoped_ptr<ProcessManager> process_manager_;
   scoped_refptr<InfoMap> info_map_;
   scoped_ptr<ErrorConsole> error_console_;
   scoped_ptr<InstallVerifier> install_verifier_;
   OneShotEvent ready_;
 };
 
 }  // namespace extensions
 
 #endif  // CHROME_BROWSER_EXTENSIONS_TEST_EXTENSION_SYSTEM_H_