Use wxScopedPtr<> instead of explicit calls to "delete"

No real changes, but the code is a bit safer and hopefully more clear.

include/wx/taskbar.h

@@ -59,10 +59,14 @@ public:
     void Destroy();
 
 protected:
+    // Note: only one of the following functions should be overridden, if both
+    // of them are, GetPopupMenu() has the priority, i.e. CreatePopupMenu()
+    // won't be called if GetPopupMenu() returns a non-null pointer.
+
     // creates menu to be displayed when user clicks on the icon
     virtual wxMenu *CreatePopupMenu() { return NULL; }
 
-    // same as CreatePopupMenu but won't destroy the menu
+    // same as CreatePopupMenu but the returned menu won't be destroyed
     virtual wxMenu *GetPopupMenu() { return NULL; }
 
 private: