On Android P the onCompletion callback isn't called if the video
is super short (like fraction of a second).

Bug: 1046347, 895776, 656015
Change-Id: I77673d3045a4b5a89b679a0bc2cef34ab0bedb88
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2027789Reviewed-by: Rayan Kanso <rayankans@chromium.org>
Commit-Queue: Finnur Thorarinsson <finnur@chromium.org>
Cr-Commit-Position: refs/heads/master@{#736843}