directfb: Switch to the new style plugins

The plugin might advertize more keys than supported at runtime. E.g.
the directfbegl key might not be available. I would like to have a
directfb.json.in and then generate the right file or if moc would
pre-process the file...

Change-Id: Ia8ad4e1367c06f5e35d02822d4f830ce1e9dc577
Reviewed-by: Jørgen Lind <jorgen.lind@nokia.com>

src/plugins/platforms/directfb/directfb.json

@@ -0,0 +1,3 @@
+{
+    "Keys": [ "directfb", "directfbegl" ]
+}

src/plugins/platforms/directfb/directfb.pro

@@ -43,3 +43,5 @@ directfbegl: {
 CONFIG += qpa/genericunixfontdatabase
 target.path += $$[QT_INSTALL_PLUGINS]/platforms
 INSTALLS += target
+
+OTHER_FILES += directfb.json

src/plugins/platforms/directfb/main.cpp

@@ -57,6 +57,8 @@ QT_BEGIN_NAMESPACE
 
 class QDirectFbIntegrationPlugin : public QPlatformIntegrationPlugin
 {
+    Q_OBJECT
+    Q_PLUGIN_METADATA(IID "org.qt-project.Qt.QPlatformIntegrationFactoryInterface" FILE "directfb.json")
 public:
     QStringList keys() const;
     QPlatformIntegration *create(const QString&, const QStringList&);
@@ -86,6 +88,6 @@ QPlatformIntegration * QDirectFbIntegrationPlugin::create(const QString& system,
     return integration;
 }
 
-Q_EXPORT_PLUGIN2(directfb, QDirectFbIntegrationPlugin)
-
 QT_END_NAMESPACE
+
+#include "main.moc"