Accessibility: Handle a missed case when clicking focused views.

The clicking logic was missing the case where a child of the accessibility
focused view reacts to the injected down up events for clicking. This
results of a whole class of views being non-interactive. Now if an event
is targeting accessibility focus and the dispatching view group has this
focus, we clear the flag before dispatching to children, so they can
handle the event rather ignoring it becuase they are not accessibility
focused.

bug:19252492

Change-Id: I6ac25bb7a50b35bb638ca4bfb9fc4198d08c2d4d