URLFetcher won't call delegate until file is closed.

net/url_request/url_fetcher_response_writer.cc

Index: net/url_request/url_fetcher_response_writer.cc
diff --git a/net/url_request/url_fetcher_response_writer.cc b/net/url_request/url_fetcher_response_writer.cc
index cb30dad8089efd6acd2d699126782cce3d147c45..a7d5b5a8a24e8050de7c65d8760ba274dc690800 100644
--- a/net/url_request/url_fetcher_response_writer.cc
+++ b/net/url_request/url_fetcher_response_writer.cc
@@ -102,8 +102,19 @@ int URLFetcherFileWriter::Write(IOBuffer* buffer,
 }
 
 int URLFetcherFileWriter::Finish(const CompletionCallback& callback) {
+  int result = file_stream_->Close(base::Bind(
+      &URLFetcherFileWriter::CloseComplete,
+      weak_factory_.GetWeakPtr(), callback));
+  if (result != ERR_IO_PENDING)
+    file_stream_.reset();
+  return result;
+}
+
+void URLFetcherFileWriter::CloseComplete(const CompletionCallback& callback,
+                                         int result) {
+  // Destroy |file_stream_| whether or not the close succeeded.
   file_stream_.reset();
-  return OK;
+  callback.Run(result);
 }
 
 void URLFetcherFileWriter::DidWrite(const CompletionCallback& callback,