Fix webview example for use with QtWebEngine.

When the QtWebEngine is used as a back-end we need to call
QtWebEngine::initialize() or the example will fail as OpenGL context
sharing needs to be enabled.

Task-number: QTBUG-42745
Change-Id: I27ffc4043f759470f4d40441e62de2ba10728a01
Reviewed-by: Caroline Chao <caroline.chao@theqtcompany.com>

examples/webview/webview/main.cpp

@@ -47,6 +47,10 @@
 #include <QQmlApplicationEngine>
 #include <QtQml/QQmlContext>
 
+#ifdef QT_WEBVIEW_WEBENGINE_BACKEND
+#include <QtWebEngine>
+#endif // QT_WEBVIEW_WEBENGINE_BACKEND
+
 // Workaround: As of Qt 5.4 QtQuick does not expose QUrl::fromUserInput.
 class Utils : public QObject {
     Q_OBJECT
@@ -68,6 +72,9 @@ QUrl Utils::fromUserInput(const QString& userInput)
 int main(int argc, char *argv[])
 {
     QGuiApplication app(argc, argv);
+#ifdef QT_WEBVIEW_WEBENGINE_BACKEND
+    QtWebEngine::initialize();
+#endif // QT_WEBVIEW_WEBENGINE_BACKEND
     QCommandLineParser parser;
     QCoreApplication::setApplicationVersion(QT_VERSION_STR);
     parser.setApplicationDescription("QtWebView Browser Example");

examples/webview/webview/webview.pro

@@ -2,6 +2,11 @@ TEMPLATE = app
 
 QT += qml quick
 
+qtHaveModule(webengine) {
+        QT += webengine
+        DEFINES += QT_WEBVIEW_WEBENGINE_BACKEND
+}
+
 SOURCES += main.cpp
 
 RESOURCES += qml.qrc