angular/angular.js — pull request #5913 by lee-elenbaas (2014-01-21 17:01:47+00:00)
Title: Use exposed equals inside watch and equals

This will allow using the proxy pattern for providing better equals implementation for specific cases

very good when you use an existing widget that performs watch on some property that you can provide a faster way to equal check it but you want to do it without changing the widget code