1273834 - getComputedStyle().transform/opacity should return style values updated by TimeStamp::Now() instead of the most recent refresh time on busy frame.

Status: NEW

(Core :: CSS Parsing and Computation, defect)

Description

[Hiroyuki Ikezoe (:hiro)]

Attachment: An example

This bug is related to bug 1167519.

getComputedStyle() flushes styles but it's against the most recent refresh time.  If getComputedStyle() is called for styles on the compositor animations in a busy frame, we will get a different value from what we are seeing the animation on the compositor.

From CSS transition spec:

> Therefore if a script queries the computed style of a property as it is transitioning,
> it will see an intermediate value that represents the current animated value of the property

Attaching file is a modification of attachment 8610350 [details] in bug 1167519.
On Chrome getComputedStyle().transform in the file returns a value close to 230, but we don't.

Comment 1

[Brian Birtles (:birtles)]

I'm not quite sure I understand what this bug covers that bug 1167519 does not -- perhaps it is about the time in between triggering the new transition and when we update the 'from' keyframe?