[fsp] Buffer consecutive Write() calls.

chrome/browser/chromeos/file_system_provider/fileapi/backend_delegate.cc

 // Copyright 2014 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 "chrome/browser/chromeos/file_system_provider/fileapi/backend_delegate.h"
 
 #include "base/memory/scoped_ptr.h"
 #include "chrome/browser/chromeos/file_system_provider/fileapi/buffering_file_stream_reader.h"
+#include "chrome/browser/chromeos/file_system_provider/fileapi/buffering_file_stream_writer.h"
 #include "chrome/browser/chromeos/file_system_provider/fileapi/file_stream_reader.h"
 #include "chrome/browser/chromeos/file_system_provider/fileapi/file_stream_writer.h"
 #include "chrome/browser/chromeos/file_system_provider/fileapi/provider_async_file_util.h"
 #include "content/public/browser/browser_thread.h"
 #include "webkit/browser/blob/file_stream_reader.h"
 #include "webkit/browser/fileapi/file_stream_writer.h"
 #include "webkit/browser/fileapi/file_system_url.h"
 
 using content::BrowserThread;
 
 namespace chromeos {
 namespace file_system_provider {
 namespace {
 
 // Size of the stream reader internal buffer. At most this number of bytes will
 // be read ahead of the requested data.
 const int kReaderBufferSize = 512 * 1024;  // 512KB.
 
+// Size of the stream writer internal buffer. At most this number of bytes will
+// be postponed for writing.
+const int kWriterBufferSize = 512 * 1024;  // 512KB.
+
 }  // namespace
 
 BackendDelegate::BackendDelegate()
     : async_file_util_(new internal::ProviderAsyncFileUtil) {}
 
 BackendDelegate::~BackendDelegate() {}
 
 storage::AsyncFileUtil* BackendDelegate::GetAsyncFileUtil(
     storage::FileSystemType type) {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
@@ skipping 15 matching lines @@
       kReaderBufferSize));
 }
 
 scoped_ptr<storage::FileStreamWriter> BackendDelegate::CreateFileStreamWriter(
     const storage::FileSystemURL& url,
     int64 offset,
     storage::FileSystemContext* context) {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
   DCHECK_EQ(storage::kFileSystemTypeProvided, url.type());
 
-  return scoped_ptr<storage::FileStreamWriter>(
-      new FileStreamWriter(url, offset));
+  return scoped_ptr<storage::FileStreamWriter>(new BufferingFileStreamWriter(
+      scoped_ptr<storage::FileStreamWriter>(new FileStreamWriter(url, offset)),
+      kWriterBufferSize));
 }
 
 }  // namespace file_system_provider
 }  // namespace chromeos