Ignore instance times from endElement*() for inactive timed elements

When endElementAt()/endElement() is trying to add a new instance time
and there's no active interval, just ignore the new instance time.

Spec:

  "While the element is not active, any end specification of the
   event is ignored."

(https://www.w3.org/TR/2001/REC-smil-animation-20010904/#Timing-EventSensitivity)

Bug: 241742
Change-Id: Ic3333698ac275eff32bd87f5e0205c1004c3e2d4
Reviewed-on: https://chromium-review.googlesource.com/c/1400663
Reviewed-by: Stephen Chenney <schenney@chromium.org>
Commit-Queue: Fredrik Söderquist <fs@opera.com>
Cr-Commit-Position: refs/heads/master@{#620752}
2 files changed