Move Extension into extensions namespace

chrome/browser/extensions/app_sync_data.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_APP_SYNC_DATA_H_
 #define CHROME_BROWSER_EXTENSIONS_APP_SYNC_DATA_H_
 #pragma once
 
 #include "chrome/browser/extensions/extension_sync_data.h"
 #include "chrome/common/string_ordinal.h"
 #include "sync/api/sync_change.h"
 
-class Extension;
 class SyncData;
 namespace sync_pb {
 class AppSpecifics;
 }
 
 namespace extensions {
 
+class Extension;
 class ExtensionSyncData;
 
 // A class that encapsulates the synced properties of an Application.
 class AppSyncData {
  public:
   AppSyncData();
   explicit AppSyncData(const SyncData& sync_data);
   explicit AppSyncData(const SyncChange& sync_change);
   AppSyncData(const Extension& extension,
               bool enabled,
@@ skipping 43 matching lines @@
   ExtensionSyncData extension_sync_data_;
   std::string notifications_client_id_;
   bool notifications_disabled_;
   StringOrdinal app_launch_ordinal_;
   StringOrdinal page_ordinal_;
 };
 
 }  // namespace extensions
 
 #endif  // CHROME_BROWSER_EXTENSIONS_APP_SYNC_DATA_H_