IndexedDB: Fixed support for empty blobs.

storage/browser/fileapi/sandbox_file_stream_writer.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 "storage/browser/fileapi/sandbox_file_stream_writer.h"
 
 #include "base/files/file_util_proxy.h"
 #include "base/sequenced_task_runner.h"
 #include "net/base/io_buffer.h"
 #include "net/base/net_errors.h"
@@ skipping 119 matching lines @@
   }
   file_size_ = file_info.size;
   if (initial_offset_ > file_size_) {
     LOG(ERROR) << initial_offset_ << ", " << file_size_;
     // This shouldn't happen as long as we check offset in the renderer.
     NOTREACHED();
     initial_offset_ = file_size_;
   }
   DCHECK(!local_file_writer_.get());
   local_file_writer_.reset(FileStreamWriter::CreateForLocalFile(
-      file_system_context_->default_file_task_runner(),
-      platform_path,
-      initial_offset_,
-      FileStreamWriter::OPEN_EXISTING_FILE));
+      file_system_context_->default_file_task_runner(), platform_path,
+      initial_offset_));
 
   storage::QuotaManagerProxy* quota_manager_proxy =
       file_system_context_->quota_manager_proxy();
   if (!quota_manager_proxy) {
     // If we don't have the quota manager or the requested filesystem type
     // does not support quota, we should be able to let it go.
     allowed_bytes_to_write_ = default_quota_;
     callback.Run(net::OK);
     return;
   }
@@ skipping 84 matching lines @@
   DCHECK(cancel_callback_.is_null());
 
   // Write() is not called yet, so there's nothing to flush.
   if (!local_file_writer_)
     return net::OK;
 
   return local_file_writer_->Flush(callback);
 }
 
 }  // namespace storage