Move taskbar button from wxTopLevelWindowMSW to wxFrame.

Since there are two sub-classes of wxTopLevelWindowMSW: one is wxFrame, the
other is wxDialog. However, wxDialog have no button shown in taskbar on
windows, so the taskbar button feature should be only avaiable in wxFrame.

Author: Chaobin Zhang

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@77576 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/msw/frame.h

@@ -11,6 +11,10 @@
 #ifndef _WX_FRAME_H_
 #define _WX_FRAME_H_
 
+#if wxUSE_TASKBARBUTTON
+class WXDLLIMPEXP_FWD_ADV wxTaskBarButton;
+#endif
+
 class WXDLLIMPEXP_CORE wxFrame : public wxFrameBase
 {
 public:
@@ -109,6 +113,15 @@ public:
     virtual wxMenu* MSWFindMenuFromHMENU(WXHMENU hMenu);
 #endif // wxUSE_MENUS
 
+#if wxUSE_TASKBARBUTTON
+    // Return the taskbar button of the window.
+    //
+    // The pointer returned by this method belongs to the window and will be
+    // deleted when the window itself is, do not delete it yourself. May return
+    // NULL if the initialization of taskbar button failed.
+    wxTaskBarButton* MSWGetTaskBarButton();
+#endif // wxUSE_TASKBARBUTTON
+
 protected:
     // common part of all ctors
     void Init();
@@ -165,6 +178,10 @@ private:
     // used by IconizeChildFrames(), see comments there
     bool m_wasMinimized;
 
+#if wxUSE_TASKBARBUTTON
+    wxTaskBarButton *m_taskBarButton;
+#endif
+
     DECLARE_EVENT_TABLE()
     DECLARE_DYNAMIC_CLASS_NO_COPY(wxFrame)
 };