Revert 271459 "Remove stray platform_file.h from webkit"

trunk/src/webkit/browser/fileapi/file_system_file_stream_reader.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 "webkit/browser/fileapi/file_system_file_stream_reader.h"
 
 #include "base/files/file_util_proxy.h"
+#include "base/platform_file.h"
 #include "base/single_thread_task_runner.h"
 #include "net/base/file_stream.h"
 #include "net/base/io_buffer.h"
 #include "net/base/net_errors.h"
 #include "webkit/browser/blob/file_stream_reader.h"
 #include "webkit/browser/fileapi/file_system_context.h"
 #include "webkit/browser/fileapi/file_system_operation_runner.h"
 
 using webkit_blob::FileStreamReader;
 
@@ skipping 116 matching lines @@
 
   local_file_reader_.reset(
       FileStreamReader::CreateForLocalFile(
           file_system_context_->default_file_task_runner(),
           platform_path, initial_offset_, expected_modification_time_));
 
   callback.Run();
 }
 
 }  // namespace fileapi