Fix crash in wxMDIParentFrame dtor after taskbar branch merge.

wxFrame::m_taskBarButton needs to be initialized in its Init(), not Create(),
which is not necessarily used by the derived classes such as wxMDIParentFrame,
resulting in a guaranteed crash when deleting an uninitialized pointer later
in wxFrame dtor.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@77688 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/msw/frame.cpp

@@ -114,6 +114,10 @@ void wxFrame::Init()
 #endif
 
     m_wasMinimized = false;
+
+#if wxUSE_TASKBARBUTTON
+    m_taskBarButton = NULL;
+#endif
 }
 
 bool wxFrame::Create(wxWindow *parent,
@@ -143,7 +147,6 @@ bool wxFrame::Create(wxWindow *parent,
 #endif // wxUSE_ACCEL && __POCKETPC__
 
 #if wxUSE_TASKBARBUTTON
-    m_taskBarButton = NULL;
     static bool s_taskbarButtonCreatedMsgRegistered = false;
     if ( !s_taskbarButtonCreatedMsgRegistered )
     {