Bug
1737682 Part 1: Log whether or not we are hitting the detached state. r=mstange
There are 10 enum cases that we track internally, one of which isn't
emitted as telemetry. These cases are 0-indexed to match the enum values.
0 / NotVideo: Not used for telemetry. No video is showing.
1 / Success: We are showing exactly one video and we believe we are
hitting the video low power mode.
2 / FailMultipleVideo: There is more than one video visible.
3 / FailWindowed: The video is being viewed in windowed mode, not
fullscreen mode, so low power mode is not possible.
4 / FailOverlaid: The video has something on top of it (like captions).
5 / FailBacking: The layer directly underneath the video does not cover
the window or does not have a black background.
6 / FailMacOSVersion: The system is running a too-early version of macOS.
7 / FailPref: The user has disabled the
`gfx.core-animation.specialize-video` pref.
8 / FailSurface: The video is encoded in such a way we can't decode it to
a qualifying pixel format.
9 / FailEnqueue: The video didn't enqueue properly, and we fell back to a
non-video display path.
Differential Revision: https://phabricator.services.mozilla.com/
D129453