Screen should stay awake while video is playing, regardless of the keep screen awake setting

When viewing a video fullscreen, I'm seeing the screen staying awake, but when viewing the video in the player, the screen timeout settings are in effect and will turn the screen off.

Start by tracing the Android video player and fullscreen playback entry points, then compare how screen timeout behavior is handled in fullscreen versus the regular player. Reproduce both cases with the keep-screen-awake setting enabled and verify that the screen remains awake while video is playing in either view.

Written by the indexing model from the issue text.