loplugin:useuniqueptr in DockingWindow

Change-Id: I7a0fec27f50c58f02378a69db5d17c6f5eb62ee2
Reviewed-on: https://gerrit.libreoffice.org/53222Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>

include/vcl/dockwin.hxx

@@ -214,7 +214,7 @@ class VCL_DLLPUBLIC DockingWindow
 private:
     VclPtr<FloatingWindow> mpFloatWin;
     VclPtr<vcl::Window>    mpOldBorderWin;
-    ImplData*       mpImplData;
+    std::unique_ptr<ImplData> mpImplData;
     Point           maFloatPos;
     Point           maDockPos;
     Point           maMouseOff;

vcl/source/window/dockwin.cxx

@@ -277,7 +277,7 @@ void DockingWindow::ImplInitDockingWindowData()
     mpWindowImpl->mbDockWin = true;
     mpFloatWin     = nullptr;
     mpOldBorderWin = nullptr;
-    mpImplData     = new ImplData;
+    mpImplData.reset(new ImplData);
     mnTrackX       = 0;
     mnTrackY       = 0;
     mnTrackWidth   = 0;
@@ -391,8 +391,7 @@ void DockingWindow::dispose()
         Show( false, ShowFlags::NoFocusChange );
         SetFloatingMode(false);
     }
-    delete mpImplData;
-    mpImplData = nullptr;
+    mpImplData.reset();
     mpFloatWin.clear();
     mpOldBorderWin.clear();
     mpDialogParent.clear();