Update from https://crrev.com/311076

net/quic/quic_headers_stream.cc

 // Copyright 2013 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 "net/quic/quic_headers_stream.h"
 
 #include "base/strings/stringprintf.h"
 #include "net/quic/quic_session.h"
 
 using base::StringPiece;
@@ skipping 167 matching lines @@
 
 QuicHeadersStream::QuicHeadersStream(QuicSession* session)
     : ReliableQuicStream(kHeadersStreamId, session),
       stream_id_(kInvalidStreamId),
       fin_(false),
       frame_len_(0),
       spdy_framer_(SPDY3),
       spdy_framer_visitor_(new SpdyFramerVisitor(this)) {
   spdy_framer_.set_visitor(spdy_framer_visitor_.get());
   spdy_framer_.set_debug_visitor(spdy_framer_visitor_.get());
-  if (version() < QUIC_VERSION_21) {
-    // Prior to QUIC_VERSION_21 the headers stream is not subject to any flow
-    // control.
-    DisableFlowControl();
-  }
   // The headers stream is exempt from connection level flow control.
   DisableConnectionFlowControlForThisStream();
 }
 
 QuicHeadersStream::~QuicHeadersStream() {}
 
 size_t QuicHeadersStream::WriteHeaders(
     QuicStreamId stream_id,
     const SpdyHeaderBlock& headers,
     bool fin,
@@ skipping 70 matching lines @@
   DCHECK_EQ(kInvalidStreamId, stream_id_);
   DCHECK_EQ(0u, frame_len_);
   frame_len_ = frame_len;
 }
 
 bool QuicHeadersStream::IsConnected() {
   return session()->connection()->connected();
 }
 
 }  // namespace net