Add support for showing "elevation" icon in wxMSW buttons.

Add, document and test in the widgets sample wxButton::SetAuthNeeded().

Closes #11705.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@63421 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/button.h

@@ -64,6 +64,12 @@ class WXDLLIMPEXP_CORE wxButtonBase : public wxControl
 public:
     wxButtonBase() { }
 
+    // show the authentication needed symbol on the button: this is currently
+    // only implemented on Windows Vista and newer (on which it shows the UAC
+    // shield symbol)
+    void SetAuthNeeded(bool show = true) { DoSetAuthNeeded(show); }
+    bool GetAuthNeeded() const { return DoGetAuthNeeded(); }
+
     // show the image in the button in addition to the label: this method is
     // supported on all (major) platforms
     void SetBitmap(const wxBitmap& bitmap, wxDirection dir = wxLEFT)
@@ -170,6 +176,9 @@ protected:
     // choose the default border for this window
     virtual wxBorder GetDefaultBorder() const { return wxBORDER_NONE; }
 
+    virtual bool DoGetAuthNeeded() const { return false; }
+    virtual void DoSetAuthNeeded(bool WXUNUSED(show)) { }
+
     virtual wxBitmap DoGetBitmap(State WXUNUSED(which)) const
         { return wxBitmap(); }
     virtual void DoSetBitmap(const wxBitmap& WXUNUSED(bitmap),