Update deprecation message for MediaStream ended event.

Remove recommendation to switch to the inactive event, since that one has been removed from the spec as well.

Also remove MeasureAs annotation from the onended attribute. Addition of listeners via the attribute are already counted in addEventListenerInternal.

BUG=608795

Review-Url: https://codereview.chromium.org/2085973002
Cr-Commit-Position: refs/heads/master@{#401331}
3 files changed