Here is a link to a Plunk that demonstrates how to extend the Angular-based ui-router-tabs library to include an icon in a custom heading that toggles along with the validation state of the corresponding view.
In the image below, View 1 has some validation error, while View 2 is OK. The solution uses Angular validation, watches, and a service to implement the functionality.
Special thanks to Stack Overflow member tasseKatt for his troubleshooting assistance.
BrainStorage 