Update from https://crrev.com/311076

net/quic/reliable_quic_stream.cc

 // Copyright (c) 2012 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/reliable_quic_stream.h"
 
 #include "base/logging.h"
 #include "net/quic/iovector.h"
 #include "net/quic/quic_flow_controller.h"
 #include "net/quic/quic_session.h"
 #include "net/quic/quic_write_blocked_list.h"
 
 using base::StringPiece;
 using std::min;
 using std::string;
 
 namespace net {
 
 #define ENDPOINT (is_server_ ? "Server: " : " Client: ")
 
 namespace {
 
 struct iovec MakeIovec(StringPiece data) {
   struct iovec iov = {const_cast<char*>(data.data()),
                       static_cast<size_t>(data.size())};
   return iov;
 }
 
 size_t GetInitialStreamFlowControlWindowToSend(QuicSession* session) {
-  QuicVersion version = session->connection()->version();
-  if (version <= QUIC_VERSION_19) {
-    return session->config()->GetInitialFlowControlWindowToSend();
-  }
-
   return session->config()->GetInitialStreamFlowControlWindowToSend();
 }
 
 size_t GetReceivedFlowControlWindow(QuicSession* session) {
-  QuicVersion version = session->connection()->version();
-  if (version <= QUIC_VERSION_19) {
-    if (session->config()->HasReceivedInitialFlowControlWindowBytes()) {
-      return session->config()->ReceivedInitialFlowControlWindowBytes();
-    }
-
-    return kMinimumFlowControlSendWindow;
-  }
-
-  // Version must be >= QUIC_VERSION_21, so we check for stream specific flow
-  // control window.
   if (session->config()->HasReceivedInitialStreamFlowControlWindowBytes()) {
     return session->config()->ReceivedInitialStreamFlowControlWindowBytes();
   }
 
   return kMinimumFlowControlSendWindow;
 }
 
 }  // namespace
 
 // Wrapper that aggregates OnAckNotifications for packets sent using
@@ skipping 298 matching lines @@
 
   // How much data we want to write.
   size_t write_length = TotalIovecLength(iov, iov_count);
 
   // A FIN with zero data payload should not be flow control blocked.
   bool fin_with_zero_data = (fin && write_length == 0);
 
   if (flow_controller_.IsEnabled()) {
     // How much data we are allowed to write from flow control.
     QuicByteCount send_window = flow_controller_.SendWindowSize();
-    // TODO(rjshade): Remove connection_flow_controller_->IsEnabled() check when
-    // removing QUIC_VERSION_19.
-    if (stream_contributes_to_connection_flow_control_ &&
-        connection_flow_controller_->IsEnabled()) {
+    if (stream_contributes_to_connection_flow_control_) {
       send_window =
           min(send_window, connection_flow_controller_->SendWindowSize());
     }
 
     if (send_window == 0 && !fin_with_zero_data) {
       // Quick return if we can't send anything.
       MaybeSendBlocked();
       return QuicConsumedData(0, false);
     }
 
@@ skipping 159 matching lines @@
 
 bool ReliableQuicStream::IsFlowControlBlocked() {
   if (flow_controller_.IsBlocked()) {
     return true;
   }
   return stream_contributes_to_connection_flow_control_ &&
       connection_flow_controller_->IsBlocked();
 }
 
 }  // namespace net