Polymer/paper-button — pull request #35 by shaisgoogle (2014-11-20 08:00:55+00:00)
Title: A toggle button can now be active even before it is pressed.

Since the button ripple is created only after the first DownAction, toggle buttons that were defined as "active" in the HTML or was set as "active" through javascript had no visual effect. Now the ripple can be created during the activeChanged event if not previously created.
HTML test markup: