Fix a bug when a QUIC session is closed during the call to InitializeSession. This seems to be able…

net/quic/quic_stream_factory.cc

Index: net/quic/quic_stream_factory.cc
diff --git a/net/quic/quic_stream_factory.cc b/net/quic/quic_stream_factory.cc
index 51b3b9df919ffbcd05ecdad72cd305e964c5b379..404ed1935b70f21f5e74960ee84adddeae61f129 100644
--- a/net/quic/quic_stream_factory.cc
+++ b/net/quic/quic_stream_factory.cc
@@ -888,9 +888,17 @@ int QuicStreamFactory::CreateSession(
       server_info.Pass(), config,
       base::MessageLoop::current()->message_loop_proxy().get(),
       net_log.net_log());
+  all_sessions_[*session] = server_id;  // owning pointer
   (*session)->InitializeSession(server_id,  &crypto_config_,
                                 quic_crypto_client_stream_factory_);
-  all_sessions_[*session] = server_id;  // owning pointer
+  bool closed_during_initialize = !ContainsKey(all_sessions_, *session);
+  UMA_HISTOGRAM_BOOLEAN("Net.QuicSession.ClosedDuringInitializeSession",
+                        closed_during_initialize);
+  if (closed_during_initialize) {
+    DLOG(DFATAL) << "Session closed during initialize";
+    *session = NULL;
+    return ERR_CONNECTION_CLOSED;
+  }
   return OK;
 }