Merge 159454 - Flush at the end of local file writing in FileWriter API.

net/base/file_stream.cc

Index: net/base/file_stream.cc
===================================================================
--- net/base/file_stream.cc	(revision 160294)
+++ net/base/file_stream.cc	(working copy)
@@ -78,10 +78,14 @@
   return impl_.Truncate(bytes);
 }
 
-int FileStream::Flush() {
-  return impl_.Flush();
+int FileStream::Flush(const CompletionCallback& callback) {
+  return impl_.Flush(callback);
 }
 
+int FileStream::FlushSync() {
+  return impl_.FlushSync();
+}
+
 void FileStream::EnableErrorStatistics() {
   impl_.EnableErrorStatistics();
 }