GitLab

cancelValuesAndHoldAtTime(time) should cancel all events after time |time|
and when the context current time reaches |time|, the automation value
that is current at that time is held as if setValueAtTime were called
with the appropriate value and time.

Spec: https://webaudio.github.io/web-audio-api/#widl-AudioParam-cancelAndHoldAtTime-AudioParam-double-cancelTime
Intent: https://groups.google.com/a/chromium.org/d/msg/blink-dev/IftXib6yFyw/CLoxngG9BgAJ

BUG=432934
TEST=audioparam-cancel-scheduled-values.html

Review-Url: https://codereview.chromium.org/1533103002
Cr-Commit-Position: refs/heads/master@{#442916}