Reduce dependencies on QtGraphicalEffects

- Make QtGraphicalEffects optional in tests
- Mention that QtGraphicalEffects is required for relevant examples

Change-Id: I3ac7d06add931e0a10c3df7edc4e458ba5519c75
Reviewed-by: Laszlo Agocs <laszlo.agocs@qt.io>

examples/quickcontrols2/imagine/automotive/doc/src/qtquickcontrols2-automotive.qdoc

@@ -36,6 +36,8 @@
     This example demonstrates how custom Imagine style assets can be used to
     style an automotive user interface.
 
+    \note This example requires \l {Qt Graphical Effects}.
+
     \image qtquickcontrols2-automotive.png
 
     \include examples-run.qdocinc

tests/auto/qquickapplicationwindow/tst_qquickapplicationwindow.cpp

@@ -763,6 +763,9 @@ void tst_QQuickApplicationWindow::focusAfterPopupClosed()
 
 void tst_QQuickApplicationWindow::clearFocusOnDestruction()
 {
+    if (!canImportModule("import QtGraphicalEffects 1.15; DropShadow {}"))
+        QSKIP("Test requires QtGraphicalEffects");
+
     QQmlEngine engine;
     QQmlComponent component(&engine);
     component.loadUrl(testFileUrl("clearfocusondestruction.qml"));

tests/auto/qquickpopup/tst_qquickpopup.cpp

@@ -1266,6 +1266,9 @@ void tst_QQuickPopup::countChanged()
 // QTBUG-73243
 void tst_QQuickPopup::toolTipCrashOnClose()
 {
+    if (!canImportModule("import QtGraphicalEffects 1.15; DropShadow {}"))
+        QSKIP("Test requires QtGraphicalEffects");
+
     QQuickApplicationHelper helper(this, "toolTipCrashOnClose.qml");
 
     QQuickWindow *window = helper.window;

tests/auto/shared/util.cpp

@@ -108,6 +108,14 @@ QByteArray QQmlDataTest::msgComponentError(const QQmlComponent &c,
     return result.toLocal8Bit();
 }
 
+bool QQmlDataTest::canImportModule(const QString &importTestQmlSource) const
+{
+    QQmlEngine engine;
+    QQmlComponent component(&engine);
+    component.setData(importTestQmlSource.toLatin1(), QUrl());
+    return !component.isError();
+}
+
 Q_GLOBAL_STATIC(QMutex, qQmlTestMessageHandlerMutex)
 
 QQmlTestMessageHandler *QQmlTestMessageHandler::m_instance = 0;

tests/auto/shared/util.h

@@ -72,6 +72,8 @@ public:
     static QByteArray msgComponentError(const QQmlComponent &,
                                         const QQmlEngine *engine = 0);
 
+    bool canImportModule(const QString &importTestQmlSource) const;
+
 public slots:
     virtual void initTestCase();