Buttons without text are inaccessible

[marcysutton]

In material-button, we attempt to automatically add accessible names by utilizing material.services.aria to copy text content to the aria-label property. However, on buttons without text content, aria-label is injected with an empty string, allowing inaccessible components with no warning being logged to the developer.

For example: the FAB buttons in the material-button demo do not have any text, however an empty string passed through to aria.expectAttribute comes back as angular.isDefined("") === true.

[marcysutton]

The code allowing empty strings to pass through: https://github.com/angular/material/blob/master/src/services/aria/aria.js#L26

[ajoslin]

@marcysutton did you manage to get this fixed per our discussion yesterday?

[marcysutton]

@ajoslin yes, I did. I want to try and improve the warning log experience to point developers to the actual node. Looking into that now.

[marcysutton]

Fixed with 3368c93