[SPDY] Add flag and about:flags entry for SPDY/4 alpha 1

net/spdy/spdy_test_util_spdy3.cc

Index: net/spdy/spdy_test_util_spdy3.cc
diff --git a/net/spdy/spdy_test_util_spdy3.cc b/net/spdy/spdy_test_util_spdy3.cc
index 272a81223e746d01b1fd77d32fd32f6290c81f1d..31f4a6ef393911848c525570f8d493abd7974269 100644
--- a/net/spdy/spdy_test_util_spdy3.cc
+++ b/net/spdy/spdy_test_util_spdy3.cc
@@ -754,6 +754,7 @@ SpdySessionDependencies::SpdySessionDependencies()
       enable_ping(false),
       enable_user_alternate_protocol_ports(false),
       enable_spdy_31(false),
+      enable_spdy_4(false),
       stream_initial_recv_window_size(kSpdyStreamInitialWindowSize),
       time_func(&base::TimeTicks::Now),
       net_log(NULL) {
@@ -780,6 +781,7 @@ SpdySessionDependencies::SpdySessionDependencies(ProxyService* proxy_service)
       enable_ping(false),
       enable_user_alternate_protocol_ports(false),
       enable_spdy_31(false),
+      enable_spdy_4(false),
       stream_initial_recv_window_size(kSpdyStreamInitialWindowSize),
       time_func(&base::TimeTicks::Now),
       net_log(NULL) {}
@@ -825,6 +827,7 @@ net::HttpNetworkSession::Params SpdySessionDependencies::CreateSessionParams(
   params.enable_user_alternate_protocol_ports =
       session_deps->enable_user_alternate_protocol_ports;
   params.spdy_default_protocol =
+      session_deps->enable_spdy_4 ? kProtoSPDY4a1 :
       session_deps->enable_spdy_31 ? kProtoSPDY31 : kProtoSPDY3;
   params.spdy_stream_initial_recv_window_size =
       session_deps->stream_initial_recv_window_size;