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

webkit/browser/fileapi/local_file_stream_writer_unittest.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/local_file_stream_writer.h"
 
 #include <string>
 
 #include "base/callback.h"
 #include "base/file_util.h"
@@ skipping 62 matching lines @@
     base::WriteFile(path, data.c_str(), data.size());
     return path;
   }
 
   base::MessageLoopProxy* file_task_runner() const {
     return file_thread_.message_loop_proxy().get();
   }
 
   LocalFileStreamWriter* CreateWriter(const base::FilePath& path,
                                       int64 offset) {
-    return new LocalFileStreamWriter(file_task_runner(), path, offset);
+    return new LocalFileStreamWriter(file_task_runner(), path, offset,
+        FileStreamWriter::OPEN_EXISTING_FILE);
   }
 
  private:
   base::MessageLoopForIO message_loop_;
   base::Thread file_thread_;
   base::ScopedTempDir temp_dir_;
 };
 
 void NeverCalled(int unused) {
   ADD_FAILURE();
@@ skipping 73 matching lines @@
       writer->Write(buffer.get(), buffer->size(), base::Bind(&NeverCalled));
   ASSERT_EQ(net::ERR_IO_PENDING, result);
 
   net::TestCompletionCallback callback;
   writer->Cancel(callback.callback());
   int cancel_result = callback.WaitForResult();
   EXPECT_EQ(net::OK, cancel_result);
 }
 
 }  // namespace fileapi