[SPDY] Do not advertise SPDY/2 by default

net/http/http_stream_factory.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_HTTP_HTTP_STREAM_FACTORY_H_
 #define NET_HTTP_HTTP_STREAM_FACTORY_H_
 
 #include <list>
 #include <string>
 #include <vector>
@@ skipping 247 matching lines @@
   static bool force_spdy_always() { return force_spdy_always_; }
 
   // Add a URL to exclude from forced SPDY.
   static void add_forced_spdy_exclusion(const std::string& value);
   // Check if a HostPortPair is excluded from using spdy.
   static bool HasSpdyExclusion(const HostPortPair& endpoint);
 
   // Sets http/1.1 as the only protocol supported via NPN or Alternate-Protocol.
   static void EnableNpnHttpOnly();
 
-  // Sets http/1.1, quic and spdy/2 (the default spdy protocol) as the protocols
-  // supported via NPN or Alternate-Protocol.
-  static void EnableNpnSpdy();
-
-  // Sets http/1.1, quic, spdy/2, and spdy/3 as the protocols supported via NPN
-  // or Alternate-Protocol.
+  // Sets http/1.1, quic, and spdy/3 as the protocols supported via
+  // NPN or Alternate-Protocol.
   static void EnableNpnSpdy3();
 
-  // Sets http/1.1, quic, spdy/2, spdy/3, and spdy/3.1 as the protocols
+  // Sets http/1.1, quic, spdy/3, and spdy/3.1 as the protocols
   // supported via NPN or Alternate-Protocol.
   static void EnableNpnSpdy31();
 
-  // Sets http/1.1, quic, spdy/2, spdy/3, spdy/3.1, and spdy/4a2 as
-  // the protocols supported via NPN or Alternate-Protocol.
+  // Sets http/1.1, quic, spdy/2, spdy/3, and spdy/3.1 as the
+  // protocols supported via NPN or Alternate-Protocol.
+  static void EnableNpnSpdy31WithSpdy2();
+
+  // Sets http/1.1, quic, spdy/3, spdy/3.1, and spdy/4a2 as the
+  // protocols supported via NPN or Alternate-Protocol.
   static void EnableNpnSpdy4a2();
 
-  // Sets http/1.1, quic, spdy/2, spdy/3, spdy/3.1, spdy/4a2, and
-  // http/2 draft 04 as the protocols supported via NPN or
-  // Alternate-Protocol.
+  // Sets http/1.1, quic, spdy/3, spdy/3.1, spdy/4a2, and http/2 draft
+  // 04 as the protocols supported via NPN or Alternate-Protocol.
   static void EnableNpnHttp2Draft04();
 
   // Sets the protocols supported by NPN (next protocol negotiation) during the
   // SSL handshake as well as by HTTP Alternate-Protocol.
   static void SetNextProtos(const std::vector<NextProto>& value);
   static bool has_next_protos() { return next_protos_ != NULL; }
   static const std::vector<std::string>& next_protos() {
     return *next_protos_;
   }
 
@@ skipping 13 matching lines @@
   static bool force_spdy_over_ssl_;
   static bool force_spdy_always_;
   static std::list<HostPortPair>* forced_spdy_exclusions_;
 
   DISALLOW_COPY_AND_ASSIGN(HttpStreamFactory);
 };
 
 }  // namespace net
 
 #endif  // NET_HTTP_HTTP_STREAM_FACTORY_H_