No media-file validation mode for DeviceMediaAsyncUtil.

chrome/browser/media_galleries/fileapi/mtp_file_stream_reader.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/media_galleries/fileapi/mtp_file_stream_reader.h"
 
 #include <algorithm>
 
 #include "base/numerics/safe_conversions.h"
 #include "base/platform_file.h"
@@ skipping 49 matching lines @@
       success_callback,
       base::Bind(&CallCompletionCallbackWithPlatformFileError, error_callback));
 }
 
 }  // namespace
 
 MTPFileStreamReader::MTPFileStreamReader(
     fileapi::FileSystemContext* file_system_context,
     const fileapi::FileSystemURL& url,
     int64 initial_offset,
-    const base::Time& expected_modification_time)
+    const base::Time& expected_modification_time,
+    bool do_media_header_validation)
     : file_system_context_(file_system_context),
       url_(url),
       current_offset_(initial_offset),
       expected_modification_time_(expected_modification_time),
-      media_header_validated_(false),
+      media_header_validated_(!do_media_header_validation),
       weak_factory_(this) {
 }
 
 MTPFileStreamReader::~MTPFileStreamReader() {
 }
 
 int MTPFileStreamReader::Read(net::IOBuffer* buf, int buf_len,
                               const net::CompletionCallback& callback) {
   DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
 
@@ skipping 100 matching lines @@
     const base::File::Info& file_info) {
   DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
 
   if (!VerifySnapshotTime(expected_modification_time_, file_info)) {
     callback.Run(net::ERR_UPLOAD_FILE_CHANGED);
     return;
   }
 
   callback.Run(file_info.size);
 }