[media] Enable MojoVideoDecoder by default.

Experiments have been uneventful for many weeks. Enable by default for M72.

TimeToFirstFrame is negatively impacted by this change, as the startup IPC now
hops throught the browser where before it went directly over the GPU channel.
The cost is typically less than 30ms. Reconfigurations are faster because
PictureBuffer allocation no longer requires any IPC.

Bug: 522298
Change-Id: I40ea00150f7dadfe2319e2cdb27e3be5f29a702c
Reviewed-on: https://chromium-review.googlesource.com/c/1315940
Commit-Queue: Dan Sanders <sandersd@chromium.org>
Reviewed-by: Frank Liberato <liberato@chromium.org>
Cr-Commit-Position: refs/heads/master@{#605752}
2 files changed