Extract external file systems handling from isolated context.

chrome/browser/chromeos/drive/drive_file_system_proxy.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_CHROMEOS_DRIVE_DRIVE_FILE_SYSTEM_PROXY_H_
 #define CHROME_BROWSER_CHROMEOS_DRIVE_DRIVE_FILE_SYSTEM_PROXY_H_
 
 #include "chrome/browser/chromeos/drive/drive_file_error.h"
-#include "webkit/chromeos/fileapi/remote_file_system_proxy.h"
+#include "webkit/fileapi/remote_file_system_proxy.h"
 
 namespace fileapi {
 class FileSystemURL;
 }
 
 namespace drive {
 
 class DriveEntryProto;
 class DriveFileSystemInterface;
 
@@ skipping 167 matching lines @@
   // DriveFileSystem is owned by Profile, which outlives DriveFileSystemProxy,
   // which is owned by CrosMountPointProvider (i.e. by the time Profile is
   // removed, the file manager is already gone). Hence it's safe to use this as
   // a raw pointer.
   DriveFileSystemInterface* file_system_;
 };
 
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_CHROMEOS_DRIVE_DRIVE_FILE_SYSTEM_PROXY_H_