Bug 1602502 - If proxy connect is not used, don't call HttpProxyResponseToErrorCode() r=dragana

Differential Revision: https://phabricator.services.mozilla.com/D56871

--HG--
extra : moz-landing-system : lando

netwerk/protocol/http/TunnelUtils.cpp

@@ -1169,7 +1169,10 @@ void SpdyConnectTransaction::MapStreamToHttpConnection(
   mTunnelStreamOut = new OutputStreamShim(this, mIsWebsocket);
   mTunneledConn = new nsHttpConnection();
 
-  if (httpResponseCode != 200) {
+  // If httpResponseCode is -1, it means that proxy connect is not used. We
+  // should not call HttpProxyResponseToErrorCode(), since this will create a
+  // shim error.
+  if (httpResponseCode > 0 && httpResponseCode != 200) {
     nsresult err = HttpProxyResponseToErrorCode(httpResponseCode);
     if (NS_FAILED(err)) {
       CreateShimError(err);