Query the native side to decide to play when going into full screen mode

Previously we save the state in Java side, but it is better to check with
native side since the exact state is already there.
This will help to get the updated state from javascript too.

bug:5765848

Webkit side change:
https://android-git.corp.google.com/g/#/c/157866/

Change-Id: Id0316b694c1597b50a1c3b123b31efc6b0fac706