Add a parameter to FileStreamWriter::CreateForLocalFile to allow creating new

webkit/browser/fileapi/isolated_file_system_backend.cc

Index: webkit/browser/fileapi/isolated_file_system_backend.cc
diff --git a/webkit/browser/fileapi/isolated_file_system_backend.cc b/webkit/browser/fileapi/isolated_file_system_backend.cc
index a8acffb4d84d7c6adb932bb8d2e041e45d80f39a..98944883758f2871ed0ab688989c4dc8aac42d5f 100644
--- a/webkit/browser/fileapi/isolated_file_system_backend.cc
+++ b/webkit/browser/fileapi/isolated_file_system_backend.cc
@@ -122,8 +122,12 @@ 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_FILE));
 }
 
 FileSystemQuotaUtil* IsolatedFileSystemBackend::GetQuotaUtil() {