loplugin:useuniqueptr in ScZoomSliderWnd

Change-Id: If6cc62d08fbd589f332514e01a42aae8f919e68f
Reviewed-on: https://gerrit.libreoffice.org/56552
Tested-by: Jenkins
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>

sc/source/ui/cctrl/tbzoomsliderctrl.cxx

@@ -234,7 +234,7 @@ ScZoomSliderWnd::~ScZoomSliderWnd()
 
 void ScZoomSliderWnd::dispose()
 {
-    delete mpImpl;
+    mpImpl.reset();
     vcl::Window::dispose();
 }
 

sc/source/ui/inc/tbzoomsliderctrl.hxx

@@ -40,7 +40,7 @@ class ScZoomSliderWnd: public vcl::Window
 {
 private:
     struct ScZoomSliderWnd_Impl;
-    ScZoomSliderWnd_Impl* mpImpl;
+    std::unique_ptr<ScZoomSliderWnd_Impl> mpImpl;
     Size aLogicalSize;
     css::uno::Reference<css::frame::XDispatchProvider> m_xDispatchProvider;