Add Flush() method to ByteStream.

content/browser/byte_stream.cc

Index: content/browser/byte_stream.cc
diff --git a/content/browser/byte_stream.cc b/content/browser/byte_stream.cc
index f83e8c31641f7ee4a1763ec662e1d1d36439bb75..8031815c6075eeabd308fef5130e328752c4af50 100644
--- a/content/browser/byte_stream.cc
+++ b/content/browser/byte_stream.cc
@@ -55,6 +55,7 @@ class ByteStreamWriterImpl : public ByteStreamWriter {
   // Overridden from ByteStreamWriter.
   virtual bool Write(scoped_refptr<net::IOBuffer> buffer,
                      size_t byte_count) OVERRIDE;
+  virtual void Flush() OVERRIDE;
   virtual void Close(DownloadInterruptReason status) OVERRIDE;
   virtual void RegisterCallback(const base::Closure& source_callback) OVERRIDE;
 
@@ -215,6 +216,12 @@ bool ByteStreamWriterImpl::Write(
   return (input_contents_size_ + output_size_used_ <= total_buffer_size_);
 }
 
+void ByteStreamWriterImpl::Flush() {
+  DCHECK(my_task_runner_->RunsTasksOnCurrentThread());
+  if (input_contents_size_ > 0)
+    PostToPeer(false, DOWNLOAD_INTERRUPT_REASON_NONE);
+}
+
 void ByteStreamWriterImpl::Close(
     DownloadInterruptReason status) {
   DCHECK(my_task_runner_->RunsTasksOnCurrentThread());