[qtlocation] Start Geoclue client position interface asynchronously. …

…Contributes to JB#38358

Previously, the geoclue client position interface was started via
an asynchronous method call.  This one could stall for multiple
seconds if the dbus call required the geoclue service to be started.

This commit replaces it with an asynchronous call which doesn't stall
the GUI thread.

Contributes to JB#38358

src/plugins/position/geoclue/qgeocluemaster.cpp

@@ -80,6 +80,22 @@ bool QGeoclueMaster::hasMasterClient() const
     return m_client && m_masterPosition;
 }
 
+void createGeoclueMasterClientPositionCallback(GeoclueMasterClient *,
+                                               GeocluePosition *position,
+                                               GError *error,
+                                               QGeoclueMaster *geoclueMaster)
+{
+    if (error) {
+        qCritical("QGeoclueMaster failed to get master position object");
+        g_error_free(error);
+        g_object_unref(geoclueMaster->m_client);
+        geoclueMaster->m_client = 0;
+        return;
+    }
+
+    geoclueMaster->m_masterPosition = position;
+}
+
 bool QGeoclueMaster::createMasterClient(GeoclueAccuracyLevel accuracy, GeoclueResourceFlags resourceFlags)
 {
     Q_ASSERT(!m_client && !m_masterPosition);
@@ -121,13 +137,7 @@ bool QGeoclueMaster::createMasterClient(GeoclueAccuracyLevel accuracy, GeoclueRe
 
     // Need to create the master position interface even though it will not be used, otherwise
     // GetPositionProvider always returns empty strings.
-    m_masterPosition = geoclue_master_client_create_position(m_client, 0);
-    if (!m_masterPosition) {
-        qCritical("QGeoclueMaster failed to get master position object");
-        g_object_unref(m_client);
-        m_client = 0;
-        return false;
-    }
+    geoclue_master_client_create_position_async(m_client, reinterpret_cast<CreatePositionCallback>(createGeoclueMasterClientPositionCallback), this);
 
     return true;
 }

src/plugins/position/geoclue/qgeocluemaster.h

@@ -61,6 +61,10 @@ class QGeoclueMaster
 private:
     GeoclueMasterClient *m_client;
     GeocluePosition *m_masterPosition;
+    friend void createGeoclueMasterClientPositionCallback(GeoclueMasterClient *,
+                                                          GeocluePosition *position,
+                                                          GError *error,
+                                                          QGeoclueMaster *geoclueMaster);
 
     QObject *m_handler;
 };