SDA: Fix start time calculation when changing timelines.

We don't necessarily know the correct start time when changing
timelines. Thus, if the animation is already running, we should
fall back to using a deferred start time similar to when playing
an animation attached to a scroll timeline.

While fixing this issue, it became apparent that there was an error
in how we normalized time based animations.  The full timeline
duration is used even if the animation range aligns with only a
portion of the timeline.  This bug does not manifest if using duration
auto, but does appear if using an explicit duration.

Bug: 1450710
Change-Id: I82ea3279af1ecaaa914614d6f07460511634d8a7
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4582749
Commit-Queue: Kevin Ellis <kevers@chromium.org>
Reviewed-by: Robert Flack <flackr@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1152602}