Add media file validation to utility process

media/filters/file_data_source.cc

 // 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.
 
 #include "media/filters/file_data_source.h"
 
 #include <algorithm>
 
 #include "base/logging.h"
 
 namespace media {
 
 FileDataSource::FileDataSource()
     : force_read_errors_(false),
       force_streaming_(false) {
 }
 
 bool FileDataSource::Initialize(const base::FilePath& file_path) {
   DCHECK(!file_.IsValid());
 
   if (!file_.Initialize(file_path))
     return false;
 
   UpdateHostBytes();
   return true;
 }
 
+bool FileDataSource::InitializeFromPlatformFile(
+    const base::PlatformFile& file) {
+  DCHECK(!file_.IsValid());
+
+  if (!file_.Initialize(file))
+    return false;
+
+  UpdateHostBytes();
+  return true;
+}
+
 void FileDataSource::set_host(DataSourceHost* host) {
   DataSource::set_host(host);
   UpdateHostBytes();
 }
 
 void FileDataSource::Stop(const base::Closure& callback) {
   callback.Run();
 }
 
 void FileDataSource::Read(int64 position, int size, uint8* data,
@@ skipping 31 matching lines @@
 FileDataSource::~FileDataSource() {}
 
 void FileDataSource::UpdateHostBytes() {
   if (host() && file_.IsValid()) {
     host()->SetTotalBytes(file_.length());
     host()->AddBufferedByteRange(0, file_.length());
   }
 }
 
 }  // namespace media