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

chrome/browser/extensions/api/image_writer_private/operation_manager.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 CHROME_BROWSER_EXTENSIONS_API_IMAGE_WRITER_PRIVATE_OPERATION_MANAGER_H_
 #define CHROME_BROWSER_EXTENSIONS_API_IMAGE_WRITER_PRIVATE_OPERATION_MANAGER_H_
 
 #include <map>
 #include <string>
 #include "base/bind.h"
 #include "base/callback.h"
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
 #include "base/scoped_observer.h"
 #include "chrome/browser/extensions/api/image_writer_private/image_writer_private_api.h"
 #include "chrome/browser/extensions/api/image_writer_private/operation.h"
 #include "chrome/common/extensions/api/image_writer_private.h"
 #include "content/public/browser/notification_observer.h"
 #include "content/public/browser/notification_registrar.h"
 #include "extensions/browser/browser_context_keyed_api_factory.h"
 #include "extensions/browser/extension_registry_observer.h"
+#include "extensions/common/extension_id.h"
 #include "url/gurl.h"
 
 namespace image_writer_api = extensions::api::image_writer_private;
 
 class Profile;
 
 namespace content {
 class BrowserContext;
 }
 
 namespace extensions {
 class ExtensionRegistry;
 
 namespace image_writer {
 
 class Operation;
 
 // Manages image writer operations for the current profile.  Including clean-up
 // and message routing.
 class OperationManager : public BrowserContextKeyedAPI,
                          public content::NotificationObserver,
                          public extensions::ExtensionRegistryObserver,
                          public base::SupportsWeakPtr<OperationManager> {
  public:
-  typedef std::string ExtensionId;
-
   explicit OperationManager(content::BrowserContext* context);
   ~OperationManager() override;
 
   void Shutdown() override;
 
   // Starts a WriteFromUrl operation.
   void StartWriteFromUrl(const ExtensionId& extension_id,
                          GURL url,
                          const std::string& hash,
                          const std::string& device_path,
@@ skipping 62 matching lines @@
 
   base::WeakPtrFactory<OperationManager> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(OperationManager);
 };
 
 }  // namespace image_writer
 }  // namespace extensions
 
 #endif  // CHROME_BROWSER_EXTENSIONS_API_IMAGE_WRITER_PRIVATE_OPERATION_MANAGER_H_