Get wxSearchCtrl text events working, and share the text event handler code among all the various wxTextCtrl-based classes.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@63415 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/osx/cocoa/private.h

@@ -173,6 +173,10 @@ public :
 
     virtual void                controlAction(WXWidget slf, void* _cmd, void* sender);
     virtual void                controlDoubleAction(WXWidget slf, void* _cmd, void *sender);
+    
+    // for wxTextCtrl-derived classes, put here since they don't all derive
+    // from the same pimpl class.
+    virtual void                controlTextDidChange();
 
 protected:
     WXWidget m_osxView;