Do not typedef ExtensionId/ID, since it's already available in extension_id.h

extensions/browser/lazy_background_task_queue.h

 // Copyright 2013 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_LAZY_BACKGROUND_TASK_QUEUE_H_
 #define EXTENSIONS_BROWSER_LAZY_BACKGROUND_TASK_QUEUE_H_
 
 #include <stddef.h>
 
 #include <map>
 #include <string>
 
 #include "base/callback_forward.h"
 #include "base/compiler_specific.h"
 #include "base/gtest_prod_util.h"
 #include "base/scoped_observer.h"
 #include "components/keyed_service/core/keyed_service.h"
 #include "content/public/browser/notification_observer.h"
 #include "content/public/browser/notification_registrar.h"
 #include "extensions/browser/extension_registry_observer.h"
+#include "extensions/common/extension_id.h"
 
 namespace content {
 class BrowserContext;
 }
 
 namespace extensions {
 class Extension;
 class ExtensionHost;
 class ExtensionRegistry;
 
@@ skipping 34 matching lines @@
   void AddPendingTask(
       content::BrowserContext* context,
       const std::string& extension_id,
       const PendingTask& task);
 
  private:
   FRIEND_TEST_ALL_PREFIXES(LazyBackgroundTaskQueueTest, ProcessPendingTasks);
 
   // A map between a BrowserContext/extension_id pair and the queue of tasks
   // pending the load of its background page.
-  typedef std::string ExtensionID;
-  typedef std::pair<content::BrowserContext*, ExtensionID> PendingTasksKey;
+  typedef std::pair<content::BrowserContext*, ExtensionId> PendingTasksKey;
   typedef std::vector<PendingTask> PendingTasksList;
   using PendingTasksMap =
       std::map<PendingTasksKey, std::unique_ptr<PendingTasksList>>;
 
   // content::NotificationObserver interface.
   void Observe(int type,
                const content::NotificationSource& source,
                const content::NotificationDetails& details) override;
 
   // ExtensionRegistryObserver interface.
@@ skipping 12 matching lines @@
   content::NotificationRegistrar registrar_;
   PendingTasksMap pending_tasks_;
 
   ScopedObserver<ExtensionRegistry, ExtensionRegistryObserver>
       extension_registry_observer_;
 };
 
 }  // namespace extensions
 
 #endif  // EXTENSIONS_BROWSER_LAZY_BACKGROUND_TASK_QUEUE_H_