Actually enable Alternate-Protocol support for QUIC.

net/http/http_stream_factory.h

Index: net/http/http_stream_factory.h
diff --git a/net/http/http_stream_factory.h b/net/http/http_stream_factory.h
index 4d8afacbfa54ce5d4774cc5c55486ccf1fde6aa3..fdcbaf0b85905c47971a7454171b399f5a68e28c 100644
--- a/net/http/http_stream_factory.h
+++ b/net/http/http_stream_factory.h
@@ -232,18 +232,19 @@ class NET_EXPORT HttpStreamFactory {
   // 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.
+  // Sets http/1.1 as the only protocol supported via NPN or Alternate-Protocol.
   static void EnableNpnHttpOnly();
 
-  // Sets http/1.1 and spdy/2 (the default spdy protocol) as the protocols
-  // supported via NPN.
+  // 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, spdy/2, and spdy/3 as the protocols supported via NPN.
+  // Sets http/1.1, quic, spdy/2, and spdy/3 as the protocols supported via NPN
+  // or Alternate-Protocol.
   static void EnableNpnSpdy3();
 
-  // Sets http/1.1, spdy/2, spdy/3, and spdy/3.1 as the protocols
-  // supported via NPN.
+  // Sets http/1.1, quic, spdy/2, spdy/3, and spdy/3.1 as the protocols
+  // supported via NPN or Alternate-Protocol.
   static void EnableNpnSpdy31();
 
   // Sets the protocols supported by NPN (next protocol negotiation) during the