added SendPageChanging/ChangedEvent() functions; fixed wxCocoa build broken by wxNotebook::ChangePage() change

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@41764 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/cocoa/notebook.mm

@@ -261,8 +261,23 @@ bool wxNotebook::SetPageImage(size_t nPage, int nImage)
     return true;
 }
 
-
 int wxNotebook::SetSelection(size_t nPage)
+{
+    const int pageOld = GetSelection();
+
+    if ( !SendPageChangingEvent(nPage) )
+        return pageOld;
+
+    int page = ChangeSelection(nPage);
+    if ( page != wxNOT_FOUND )
+    {
+        SendPageChangedEvent(pageOld);
+    }
+
+    return page;
+}
+
+int wxNotebook::ChangeSelection(size_t nPage)
 {
     wxAutoNSAutoreleasePool pool;
     [GetNSTabView() selectTabViewItemAtIndex:nPage];