winrt: Skip host lookup for http connections

While QAbstractSocket is already changed in a way that winrt only
connects to host names and does not do IP lookups, http connections
still do a lookup to check, whether to use IPv4 or IPv6. As this
information is not needed on winrt anyways and hostnames are to be
preferred over IP addresses on winrt (automatic lookup & proxy handling
internally), we skip the lookup for http as well.

Task-number: QTBUG-59989
Change-Id: Ibc11f5ac07faf23e7af508fd20ee4880b24f79a8
Reviewed-by: Maurice Kalinowski <maurice.kalinowski@qt.io>

src/network/access/qhttpnetworkconnection.cpp

@@ -644,6 +644,7 @@ QHttpNetworkReply* QHttpNetworkConnectionPrivate::queueRequest(const QHttpNetwor
         channels[0].spdyRequestsToSend.insertMulti(request.priority(), pair);
     }
 
+#ifndef Q_OS_WINRT
     // For Happy Eyeballs the networkLayerState is set to Unknown
     // untill we have started the first connection attempt. So no
     // request will be started untill we know if IPv4 or IPv6
@@ -651,6 +652,13 @@ QHttpNetworkReply* QHttpNetworkConnectionPrivate::queueRequest(const QHttpNetwor
     if (networkLayerState == Unknown || networkLayerState == HostLookupPending) {
         startHostInfoLookup();
     } else if ( networkLayerState == IPv4 || networkLayerState == IPv6 ) {
+#else // !Q_OS_WINRT
+    {
+        // Skip the host lookup part for winrt. Host lookup and proxy handling are done by Windows
+        // internally and networkLayerPreference is ignored on this platform. Instead of refactoring
+        // the whole approach we just pretend that everything important is known here.
+        networkLayerState = IPv4;
+#endif
         // this used to be called via invokeMethod and a QueuedConnection
         // It is the only place _q_startNextRequest is called directly without going
         // through the event loop using a QueuedConnection.