Thanks to Maggie (imjustsomeoneiguess) on discord for helping with a lot of this VP9 media code.
This is the first browser so far to support VP9 Non MFT
Based on FranklinDM's follow-up for the issue.
This would require browser FE changes, particularly removing the associated
code in `tabbrowser.xml`, however, that was already done in Pale Moon previously.
Other front-end applications may need to take note, though.
Based on changes from the following bugs:
* Bug 696398 - Need an api to analyze panning performance
* Bug 800031 - Include paint time in tab switch telemetry
* Bug 820167 - Enable performance measurement of tab animation
* Bug 826383 - Improve Start/Stop FrameTimeRecording for telemetry usage