Bug 977588 - [Dialer] The Active call screen does not have the option to place calls on hold.

This is not the correct flow. We need the click on the button to call CallsHandler.holdOrResumeSingleCall. And holdOrResumeSingleCall should call a method on CallScreen to set or remove the active-state class. Without doing so, the active-state will not be updated when holding/resuming via bluetooth devices (and maybe regular headsets).