SPDY - add support for spdy/2.1 to support flow control.

net/http/http_server_properties.cc

 // Copyright (c) 2011 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/http/http_server_properties.h"
 
 #include "base/logging.h"
 #include "base/stringprintf.h"
 
 namespace net {
 
 const char kAlternateProtocolHeader[] = "Alternate-Protocol";
 const char* const kAlternateProtocolStrings[] = {
   "npn-spdy/1",
   "npn-spdy/2",
+  "npn-spdy/2.1",
 };
 
 static const char* AlternateProtocolToString(AlternateProtocol protocol) {
   switch (protocol) {
     case NPN_SPDY_1:
     case NPN_SPDY_2:
+    case NPN_SPDY_21:
       return kAlternateProtocolStrings[protocol];
     case ALTERNATE_PROTOCOL_BROKEN:
       return "Broken";
     case UNINITIALIZED_ALTERNATE_PROTOCOL:
       return "Uninitialized";
     default:
       NOTREACHED();
       return "";
   }
 }
 
 std::string PortAlternateProtocolPair::ToString() const {
   return base::StringPrintf("%d:%s", port,
                             AlternateProtocolToString(protocol));
 }
 
 }  // namespace net