Qt Quick Control Application: Optional QtWidget dependency

Let the user chose whether "native styling" via QWidgets/QApplication
should be enabled or not.

Change-Id: I5eaa7b3a94d5361e62ebce61ff6b7b9216e15b80
Reviewed-by: Thomas Hartmann <Thomas.Hartmann@digia.com>

share/qtcreator/templates/wizards/projects/qmake/qtquickcontrolsapplication/app.pro

@@ -1,6 +1,10 @@
 TEMPLATE = app
 
+@if %{UseQApplication}
 QT += qml quick widgets
+@else
+QT += qml quick
+@endif
 
 SOURCES += %{MainCppFileName}
 

share/qtcreator/templates/wizards/projects/qmake/qtquickcontrolsapplication/main.cpp

@@ -1,8 +1,12 @@
 %{Cpp:LicenseTemplate}\
-%{JS: QtSupport.qtIncludes([], ["QWidgets/QApplication", "QQml/QQmlApplicationEngine"])}
+%{JS: QtSupport.qtIncludes([], [%{UseQApplication} ? "QWidgets/QApplication" : "QtGui/QGuiApplication", "QQml/QQmlApplicationEngine"])}
 int main(int argc, char *argv[])
 {
+@if %{UseQApplication}
     QApplication app(argc, argv);
+@else
+    QGuiApplication app(argc, argv);
+@endif
 
     QQmlApplicationEngine engine;
     engine.load(QUrl(QStringLiteral("qrc:/main.qml")));

share/qtcreator/templates/wizards/projects/qmake/qtquickcontrolsapplication/wizard.json

@@ -84,6 +84,17 @@
                         "uncheckedValue": false,
                         "checked": true
                     }
+                },
+                {
+                    "name": "UseQApplication",
+                    "trDisplayName": "Enable native styling. Requires dependency on the QtWidgets module.",
+                    "type": "CheckBox",
+                    "data":
+                    {
+                        "checkedValue": true,
+                        "uncheckedValue": false,
+                        "checked": true
+                    }
                 }
             ]
         },