Make new UI tests faster.
Make new UI tests faster.

The event was being raised synchronously, so it wasn't getting caught
by the waiter.  This caused each test to take 5 seconds while it waits
for the timeout.  Now the tests take <100ms.

Change-Id: Ia62423a22cff6eb6098fded43b914ae379b07a88

shaka-project/shaka-player,tvoli/shaka-player,tvoli/shaka-player,shaka-project/shaka-player,shaka-project/shaka-player,tvoli/shaka-player,shaka-project/shaka-player,tvoli/shaka-player