[SPDY] Add flag to turn on SPDY/3.1 (with per-session flow control)

net/socket/ssl_client_socket.cc

Index: net/socket/ssl_client_socket.cc
diff --git a/net/socket/ssl_client_socket.cc b/net/socket/ssl_client_socket.cc
index 7f2325846e0bce50c3d4f5fafa73bc2226883e82..478ef18c7fb4e631558167c7770aa16eaa9efe76 100644
--- a/net/socket/ssl_client_socket.cc
+++ b/net/socket/ssl_client_socket.cc
@@ -26,6 +26,8 @@ NextProto SSLClientSocket::NextProtoFromString(
     return kProtoSPDY2;
   } else if (proto_string == "spdy/3") {
     return kProtoSPDY3;
+  } else if (proto_string == "spdy/3.1") {
+    return kProtoSPDY31;
   } else {
     return kProtoUnknown;
   }
@@ -42,6 +44,8 @@ const char* SSLClientSocket::NextProtoToString(NextProto next_proto) {
       return "spdy/2";
     case kProtoSPDY3:
       return "spdy/3";
+    case kProtoSPDY31:
+      return "spdy/3.1";
     default:
       break;
   }