Return QScreen's HMONITOR handle via QPlatformNativeInterface

It is needed to be able to fetch extra information about the display via
DXGI interface.

Change-Id: Id83982eb07ade157719e430d0abcc2613409a343
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@qt.io>

src/plugins/platforms/windows/qwindowsnativeinterface.cpp

@@ -40,6 +40,7 @@
 #include "qwindowsnativeinterface.h"
 #include "qwindowsclipboard.h"
 #include "qwindowswindow.h"
+#include "qwindowsscreen.h"
 #include "qwindowscontext.h"
 #include "qwindowscursor.h"
 #include "qwindowsopenglcontext.h"
@@ -124,6 +125,21 @@ void *QWindowsNativeInterface::nativeResourceForWindow(const QByteArray &resourc
     return nullptr;
 }
 
+void *QWindowsNativeInterface::nativeResourceForScreen(const QByteArray &resource, QScreen *screen)
+{
+    if (!screen || !screen->handle()) {
+        qWarning("%s: '%s' requested for null screen or screen without handle.", __FUNCTION__, resource.constData());
+        return nullptr;
+    }
+    QWindowsScreen *bs = static_cast<QWindowsScreen *>(screen->handle());
+    int type = resourceType(resource);
+    if (type == HandleType)
+        return bs->handle();
+
+    qWarning("%s: Invalid key '%s' requested.", __FUNCTION__, resource.constData());
+    return nullptr;
+}
+
 #ifndef QT_NO_CURSOR
 void *QWindowsNativeInterface::nativeResourceForCursor(const QByteArray &resource, const QCursor &cursor)
 {

src/plugins/platforms/windows/qwindowsnativeinterface.h

@@ -74,6 +74,7 @@ public:
     void *nativeResourceForContext(const QByteArray &resource, QOpenGLContext *context) override;
 #endif
     void *nativeResourceForWindow(const QByteArray &resource, QWindow *window) override;
+    void *nativeResourceForScreen(const QByteArray &resource, QScreen *screen) override;
 #ifndef QT_NO_CURSOR
     void *nativeResourceForCursor(const QByteArray &resource, const QCursor &cursor) override;
 #endif

src/plugins/platforms/windows/qwindowsscreen.cpp

@@ -321,6 +321,11 @@ void QWindowsScreen::handleChanges(const QWindowsScreenData &newData)
     }
 }
 
+HMONITOR QWindowsScreen::handle() const
+{
+    return m_data.hMonitor;
+}
+
 QRect QWindowsScreen::virtualGeometry(const QPlatformScreen *screen) // cf QScreen::virtualGeometry()
 {
     QRect result;

src/plugins/platforms/windows/qwindowsscreen.h

@@ -104,6 +104,8 @@ public:
 
     inline void handleChanges(const QWindowsScreenData &newData);
 
+    HMONITOR handle() const;
+
 #ifndef QT_NO_CURSOR
     QPlatformCursor *cursor() const override { return m_cursor.data(); }
     const CursorPtr &cursorPtr() const { return m_cursor; }