TwoStatePreference does not fire click events.

1. Event were send in onBindView but since we have fixed the bug
   of unattached views firing accessibility events and there is
   no guarantee that the view is attached in onBindView no events
   were sent. Now posting a runnable so on the next run the UI
   tread will send the event i.e. after the view is bound and
   attached.

bug:5008841

Change-Id: I4ed914f7fb65d6896f0c55e7c46e6508d2b2f11f