Fix total frames metrics

[stefanosiano]

Description

The callback we rely on is called only when the frames change, so we cannot get the real total number of frames. We already use the same approach of JankStats. We could try to use Choreographer directly, but that's bad for performance. We have to find a way to calculate total frames. Internal doc with some considerations

[markushi]

Let's check if we can get notified if the refresh-rate changes. We could fallback to the last known refresh-rate and simply count the number of expected frames.

[romtsn]

This is done by the frame delay PR