Clean up wxDropTarget and wxWindow a bit more by moving DnD stuff fully into drop target (besides connecting and disconnecting).

Window doesn't have to know more than how to hook itself up.
Impl now performs function of event filter/adapter.

src/qt/dnd.cpp

@@ -82,13 +82,6 @@ namespace
     }
 }
 
-
-class wxDropTarget::Impl
-{
-public:
-    const QMimeData* m_pendingMimeData;
-};
-
 namespace
 {
     class PendingMimeDataSetter
@@ -110,9 +103,99 @@ namespace
     };
 }
 
+class wxDropTarget::Impl : public QObject
+{
+public:
+    explicit Impl(wxDropTarget* dropTarget) : m_dropTarget(dropTarget)
+    {
+    }
+
+    virtual bool eventFilter(QObject* watched, QEvent* event) wxOVERRIDE
+    {
+        if ( m_dropTarget != NULL )
+        {
+            switch ( event->type() )
+            {
+                case QEvent::Drop:
+                    OnDrop(event);
+                    return true;
+
+                case QEvent::DragEnter:
+                    OnEnter(event);
+                    return true;
+
+                case QEvent::DragMove:
+                    OnMove(event);
+                    return true;
+
+                case QEvent::DragLeave:
+                    OnLeave(event);
+                    return true;
+
+                default:
+                    break;
+            }
+        }
+
+        return QObject::eventFilter(watched, event);
+    }
+
+    void OnEnter(QEvent* event)
+    {
+        event->accept();
+
+        QDragEnterEvent *e = static_cast<QDragEnterEvent*>(event);
+        const QPoint where = e->pos();
+
+        PendingMimeDataSetter setter(m_pendingMimeData, e->mimeData());
+
+        wxDragResult result = m_dropTarget->OnEnter(where.x(), where.y(), DropActionToDragResult(e->proposedAction()));
+
+        e->setDropAction(DragResultToDropAction(result));
+    }
+
+    void OnLeave(QEvent* event)
+    {
+        event->accept();
+        m_dropTarget->OnLeave();
+    }
+
+    void OnMove(QEvent* event)
+    {
+        event->accept();
+
+        QDragMoveEvent *e = static_cast<QDragMoveEvent*>(event);
+        const QPoint where = e->pos();
+
+        PendingMimeDataSetter setter(m_pendingMimeData, e->mimeData());
+
+        wxDragResult result = m_dropTarget->OnDragOver(where.x(), where.y(), DropActionToDragResult(e->proposedAction()));
+
+        e->setDropAction(DragResultToDropAction(result));
+    }
+
+    void OnDrop(QEvent* event)
+    {
+        event->accept();
+
+        const QDropEvent *e = static_cast<QDropEvent*>(event);
+        const QPoint where = e->pos();
+
+        PendingMimeDataSetter setter(m_pendingMimeData, e->mimeData());
+
+        if ( m_dropTarget->OnDrop(where.x(), where.y()) )
+        {
+            m_dropTarget->OnData(where.x(), where.y(), DropActionToDragResult(e->dropAction()));
+        }
+    }
+    
+    const QMimeData* m_pendingMimeData;
+    wxDropTarget* m_dropTarget;
+};
+
 wxDropTarget::wxDropTarget(wxDataObject *dataObject)
     : wxDropTargetBase(dataObject),
-      m_pImpl(new Impl)
+      m_pImpl(new Impl(this))
 {
 }
 
@@ -163,53 +246,16 @@ wxDataFormat wxDropTarget::GetMatchingPair()
     return wxFormatInvalid;
 }
 
-void wxDropTarget::OnQtEnter(QEvent* event)
+void wxDropTarget::ConnectToQWidget(QWidget* widget)
 {
-    event->accept();
-    
-    QDragEnterEvent *e = static_cast<QDragEnterEvent*>(event);
-    const QPoint where = e->pos();
-
-    PendingMimeDataSetter setter(m_pImpl->m_pendingMimeData, e->mimeData());
-
-    wxDragResult result = OnEnter(where.x(), where.y(), DropActionToDragResult(e->proposedAction()));
-
-    e->setDropAction(DragResultToDropAction(result));
+    widget->setAcceptDrops(true);
+    widget->installEventFilter(m_pImpl);
 }
 
-void wxDropTarget::OnQtLeave(QEvent* event)
+void wxDropTarget::DisconnectFromQWidget(QWidget* widget)
 {
-    event->accept();
-    OnLeave();
-}
-
-void wxDropTarget::OnQtMove(QEvent* event)
-{
-    event->accept();
-
-    QDragMoveEvent *e = static_cast<QDragMoveEvent*>(event);
-    const QPoint where = e->pos();
-
-    PendingMimeDataSetter setter(m_pImpl->m_pendingMimeData, e->mimeData());
-
-    wxDragResult result = OnDragOver(where.x(), where.y(), DropActionToDragResult(e->proposedAction()));
-
-    e->setDropAction(DragResultToDropAction(result));
-}
-
-void wxDropTarget::OnQtDrop(QEvent* event)
-{
-    event->accept();
-
-    const QDropEvent *e = static_cast<QDropEvent*>(event);
-    const QPoint where = e->pos();
-
-    PendingMimeDataSetter setter(m_pImpl->m_pendingMimeData, e->mimeData());
-
-    if ( OnDrop(where.x(), where.y()) )
-    {
-        OnData(where.x(), where.y(), DropActionToDragResult(e->dropAction()));
-    }
+    widget->setAcceptDrops(false);
+    widget->removeEventFilter(m_pImpl);
 }
 
 //##############################################################################