use unique_ptr for mpControlFont

Change-Id: I71eed3254cf073b754c1a634315e6e739a816606
Reviewed-on: https://gerrit.libreoffice.org/42264Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>

vcl/inc/window.h

@@ -235,7 +235,8 @@ public:
     Pointer             maPointer;
     Fraction            maZoom;
     OUString            maText;
-    vcl::Font*          mpControlFont;
+    std::unique_ptr<vcl::Font>
+                        mpControlFont;
     Color               maControlForeground;
     Color               maControlBackground;
     sal_Int32           mnLeftBorder;

vcl/source/window/window.cxx

@@ -617,7 +617,6 @@ WindowImpl::WindowImpl( WindowType nType )
     mnEventListenersIteratingCount = 0;
     mnChildEventListenersIteratingCount = 0;
     mpCursor                            = nullptr;                      // cursor
-    mpControlFont                       = nullptr;                      // font properties
     mpVCLXWindow                        = nullptr;
     mpAccessibleInfos                   = nullptr;
     maControlForeground                 = Color( COL_TRANSPARENT );  // no foreground set
@@ -743,7 +742,6 @@ WindowImpl::~WindowImpl()
 {
     delete mpChildClipRegion;
     delete mpAccessibleInfos;
-    delete mpControlFont;
 }
 
 ImplWinData::ImplWinData() :

vcl/source/window/window2.cxx

@@ -475,8 +475,7 @@ void Window::SetControlFont()
 {
     if (mpWindowImpl && mpWindowImpl->mpControlFont)
     {
-        delete mpWindowImpl->mpControlFont;
-        mpWindowImpl->mpControlFont = nullptr;
+        mpWindowImpl->mpControlFont.reset();
         CompatStateChanged(StateChangedType::ControlFont);
     }
 }
@@ -496,7 +495,7 @@ void Window::SetControlFont(const vcl::Font& rFont)
         *mpWindowImpl->mpControlFont = rFont;
     }
     else
-        mpWindowImpl->mpControlFont = new vcl::Font(rFont);
+        mpWindowImpl->mpControlFont.reset( new vcl::Font(rFont) );
 
     CompatStateChanged(StateChangedType::ControlFont);
 }
@@ -1110,7 +1109,7 @@ const InputContext& Window::GetInputContext() const
 
 bool Window::IsControlFont() const
 {
-    return (mpWindowImpl->mpControlFont != nullptr);
+    return bool(mpWindowImpl->mpControlFont);
 }
 
 const Color& Window::GetControlForeground() const