Web Animations: Implement CSS Animation events

Web Animations: Implement CSS Animation events

Events are queued and dispatched from DocumentTimeline.

This doesn't correctly handle start events detected during a style recalc. In
the existing implementation these events are triggered by a timer. Here they
are deferred until the next animation frame.

BUG=258896
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=155597

[Steve Block, 2013-08-06 05:29:12]

Did you intend this to be compatible with or support the latest proposal for
events in Web Animations? If so, do you have a link to that proposal?

If I remember correctly, we discussed ordering animation events in the model
such that for start events, parents fire before children, and for end events,
the reverse order is used. It looks like that's not done here?

https://codereview.chromium.org/22123002/diff/1/Source/core/animation/css/CSS...
File Source/core/animation/css/CSSAnimations.cpp (right):

https://codereview.chromium.org/22123002/diff/1/Source/core/animation/css/CSS...
Source/core/animation/css/CSSAnimations.cpp:204: void
CSSAnimations::EventDelegate::dispatch(Document::ListenerType listenerType,
AtomicString& eventName, double elapsedTime)
Should this be called maybeDispatch(), as we only dispatch if a listener is
registered?

https://codereview.chromium.org/22123002/diff/1/Source/core/animation/css/CSS...
Source/core/animation/css/CSSAnimations.cpp:207:
m_target->document()->timeline()->addEventToDispatch(m_target,
AnimationEvent::create(eventName, m_name, elapsedTime));
We receive the calls to EventDelegate::onEventCondition() synchronously when
sampling the TimeItems, so all events will have been added to the timeline by
the time DocumentTimeline::serviceAnimations() completes, right? I ask because
when I first saw this, I thought this call would schedule the event for dispatch
on the next sample. Maybe worth a comment?

[dstockwell, 2013-08-06 06:10:02]

On 2013/08/06 05:29:12, Steve Block wrote:
> Did you intend this to be compatible with or support the latest proposal for
> events in Web Animations? If so, do you have a link to that proposal?

No, this is only intended to support CSS Animation events. We may want to change
the approach once Web Animations events are added. eg. the delegate might
replace (if you can't attain a handle on the Timed Items for a CSS Animation) or
be in addition to the Web Animations event logic, or be replaced by something
else entirely.

https://codereview.chromium.org/22123002/diff/1/Source/core/animation/css/CSS...
File Source/core/animation/css/CSSAnimations.cpp (right):

https://codereview.chromium.org/22123002/diff/1/Source/core/animation/css/CSS...
Source/core/animation/css/CSSAnimations.cpp:204: void
CSSAnimations::EventDelegate::dispatch(Document::ListenerType listenerType,
AtomicString& eventName, double elapsedTime)
On 2013/08/06 05:29:12, Steve Block wrote:
> Should this be called maybeDispatch(), as we only dispatch if a listener is
> registered?

Done.

https://codereview.chromium.org/22123002/diff/1/Source/core/animation/css/CSS...
Source/core/animation/css/CSSAnimations.cpp:207:
m_target->document()->timeline()->addEventToDispatch(m_target,
AnimationEvent::create(eventName, m_name, elapsedTime));
On 2013/08/06 05:29:12, Steve Block wrote:
> We receive the calls to EventDelegate::onEventCondition() synchronously when
> sampling the TimeItems, so all events will have been added to the timeline by
> the time DocumentTimeline::serviceAnimations() completes, right? I ask because
> when I first saw this, I thought this call would schedule the event for
dispatch
> on the next sample. Maybe worth a comment?

Almost. Start events for new animations can be triggered outside of
serviceAnimations (as mentioned in the description). I'll add some comments
here.

[Steve Block, 2013-08-06 06:31:41]

lgtm

[commit-bot: I haz the power, 2013-08-06 07:50:47]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/dstockwell@chromium.org/22123002/6001

[commit-bot: I haz the power, 2013-08-06 09:53:10]

Change committed as 155597