Blob support for IDB [Chromium]

webkit/browser/fileapi/isolated_file_system_backend.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/isolated_file_system_backend.h"
 
 #include <string>
 
 #include "base/bind.h"
 #include "base/files/file_path.h"
@@ skipping 100 matching lines @@
   return scoped_ptr<webkit_blob::FileStreamReader>(
       webkit_blob::FileStreamReader::CreateForLocalFile(
           context->default_file_task_runner(),
           url.path(), offset, expected_modification_time));
 }
 
 scoped_ptr<FileStreamWriter> IsolatedFileSystemBackend::CreateFileStreamWriter(
     const FileSystemURL& url,
     int64 offset,
     FileSystemContext* context) const {
-  return scoped_ptr<FileStreamWriter>(FileStreamWriter::CreateForLocalFile(
-      context->default_file_task_runner(), url.path(), offset));
+  return scoped_ptr<FileStreamWriter>(
+      FileStreamWriter::CreateForLocalFile(context->default_file_task_runner(),
+                                           url.path(),
+                                           offset,
+                                           FileStreamWriter::OPEN_EXISTING));
 }
 
 FileSystemQuotaUtil* IsolatedFileSystemBackend::GetQuotaUtil() {
   // No quota support.
   return NULL;
 }
 
 }  // namespace fileapi