Move some dock widget view code into the shared DockWidgetViewInterface

src/views/DockWidgetViewInterface.cpp

@@ -10,6 +10,8 @@
 */
 
 #include "DockWidgetViewInterface.h"
+#include "kddockwidgets/controllers/DockWidget.h"
+#include "kddockwidgets/controllers/DockWidget_p.h"
 
 namespace KDDockWidgets::Views {
 
@@ -18,6 +20,23 @@ DockWidgetViewInterface::DockWidgetViewInterface(Controllers::DockWidget *contro
 {
 }
 
+Controllers::Frame *DockWidgetViewInterface::frame() const
+{
+    return m_dockWidget->dptr()->frame();
+}
+
+Controllers::DockWidget *DockWidgetViewInterface::dockWidget() const
+{
+    return m_dockWidget;
+}
+
+Controllers::TitleBar *DockWidgetViewInterface::actualTitleBar() const
+{
+    if (Controllers::Frame *frame = this->frame())
+        return frame->actualTitleBar();
+    return nullptr;
+}
+
 DockWidgetViewInterface::~DockWidgetViewInterface() = default;
 
 } // namespace