Add GetURLForBrowserTab method to the external file system backend.

chrome/browser/chromeos/fileapi/mtp_file_system_backend_delegate.cc

 // Copyright 2014 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.
 
 #include "chrome/browser/chromeos/fileapi/mtp_file_system_backend_delegate.h"
 #include "chrome/browser/media_galleries/fileapi/device_media_async_file_util.h"
 #include "webkit/browser/blob/file_stream_reader.h"
 #include "webkit/browser/fileapi/file_stream_writer.h"
 #include "webkit/browser/fileapi/file_system_url.h"
 
@@ skipping 38 matching lines @@
   // TODO(kinaba): support writing.
   return scoped_ptr<storage::FileStreamWriter>();
 }
 
 storage::WatcherManager* MTPFileSystemBackendDelegate::GetWatcherManager(
     const storage::FileSystemURL& url) {
   NOTIMPLEMENTED();
   return NULL;
 }
 
+void MTPFileSystemBackendDelegate::GetURLForBrowserTab(
+    const storage::FileSystemURL& url,
+    const URLCallback& callback) {
+  callback.Run(GURL());

[mtomasz, 2014/09/04 05:30:01]

How about checking for the url.type like in #47? Note, that I don't do that in
#55, because the method is not implemented. However, this method is implemented.
Basically there is never redirection for mtp.

[hirono, 2014/09/04 06:10:59]

Done.

+}
+
 }  // namespace chromeos