ImplRestore() can be private

It is only called from other member functions.

Also, all the calls are inside conditionals that check mpData &&
mpData->mbCurVisible already, so no need to check anew in the function. Use an
assert() instead.

Change-Id: Ibcde0aa43877b64b9b0ae5117cbda1fb44ee023d

include/vcl/cursor.hxx

@@ -55,7 +55,6 @@ private:
 
 public:
     SAL_DLLPRIVATE void         ImplDraw();
-    SAL_DLLPRIVATE void         ImplRestore();
     DECL_DLLPRIVATE_LINK_TYPED( ImplTimerHdl, Timer*, void );
     SAL_DLLPRIVATE void         ImplShow( bool bDrawDirect = true );
     SAL_DLLPRIVATE void         ImplHide( bool bStopTimer );
@@ -101,6 +100,7 @@ public:
                         { return !(Cursor::operator==( rCursor )); }
 
 private:
+    void ImplRestore();
     void ImplDoShow( bool bDrawDirect, bool bRestore );
     bool ImplDoHide( bool bStop );
 };

vcl/source/window/cursor.cxx

@@ -141,11 +141,10 @@ void vcl::Cursor::ImplDraw()
 
 void vcl::Cursor::ImplRestore()
 {
-    if ( mpData && mpData->mbCurVisible )
-    {
-        ImplCursorInvert( mpData );
-        mpData->mbCurVisible = false;
-    }
+    assert( mpData && mpData->mbCurVisible );
+
+    ImplCursorInvert( mpData );
+    mpData->mbCurVisible = false;
 }
 
 void vcl::Cursor::ImplDoShow( bool bDrawDirect, bool bRestore )