Don't set QUIC's write alarm if we are connection flow control blocked.

net/quic/quic_protocol.h

 // 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.
 
 #ifndef NET_QUIC_QUIC_PROTOCOL_H_
 #define NET_QUIC_QUIC_PROTOCOL_H_
 
 #include <stddef.h>
 #include <limits>
 #include <map>
@@ skipping 257 matching lines @@
   QUIC_VERSION_19 = 19,  // Current version.
 };
 
 // This vector contains QUIC versions which we currently support.
 // This should be ordered such that the highest supported version is the first
 // element, with subsequent elements in descending order (versions can be
 // skipped as necessary).
 //
 // IMPORTANT: if you are addding to this list, follow the instructions at
 // http://sites/quic/adding-and-removing-versions
-static const QuicVersion kSupportedQuicVersions[] = {QUIC_VERSION_18,
+static const QuicVersion kSupportedQuicVersions[] = {QUIC_VERSION_19,
+                                                     QUIC_VERSION_18,
                                                      QUIC_VERSION_17,
                                                      QUIC_VERSION_16,
                                                      QUIC_VERSION_15};
 
 typedef std::vector<QuicVersion> QuicVersionVector;
 
 // Returns a vector of QUIC versions in kSupportedQuicVersions.
 NET_EXPORT_PRIVATE QuicVersionVector QuicSupportedVersions();
 
 // QuicTag is written to and read from the wire, but we prefer to use
@@ skipping 781 matching lines @@
   WriteStatus status;
   union {
     int bytes_written;  // only valid when status is OK
     int error_code;  // only valid when status is ERROR
   };
 };
 
 }  // namespace net
 
 #endif  // NET_QUIC_QUIC_PROTOCOL_H_