chrome: Cleanup class/struct forward declarations

chrome/browser/media_galleries/media_file_system_registry.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.
 
 // MediaFileSystemRegistry registers pictures directories and media devices as
 // File API filesystems and keeps track of the path to filesystem ID mappings.
 
 #ifndef CHROME_BROWSER_MEDIA_GALLERIES_MEDIA_FILE_SYSTEM_REGISTRY_H_
 #define CHROME_BROWSER_MEDIA_GALLERIES_MEDIA_FILE_SYSTEM_REGISTRY_H_
 
@@ skipping 18 matching lines @@
 class Profile;
 
 namespace content {
 class WebContents;
 }
 
 namespace extensions {
 class Extension;
 }
 
-namespace storage {
-class IsolatedContext;
-}
-
 // Contains information about a particular filesystem being provided to a
 // client, including metadata like the name and ID, and API handles like the
 // fsid (filesystem ID) used to hook up the API objects.
 struct MediaFileSystemInfo {
   MediaFileSystemInfo(const base::string16& fs_name,
                       const base::FilePath& fs_path,
                       const std::string& filesystem_id,
                       MediaGalleryPrefId pref_id,
                       const std::string& transient_device_id,
                       bool removable,
@@ skipping 91 matching lines @@
   ProfileSubscriptionMap profile_subscription_map_;
 
   std::unique_ptr<MediaFileSystemContext> file_system_context_;
 
   std::unique_ptr<GalleryWatchManager> gallery_watch_manager_;
 
   DISALLOW_COPY_AND_ASSIGN(MediaFileSystemRegistry);
 };
 
 #endif  // CHROME_BROWSER_MEDIA_GALLERIES_MEDIA_FILE_SYSTEM_REGISTRY_H_