1241672 - Need a method to fire wheel events without any flush

Status: RESOLVED FIXED

(Testing :: Mochitest, defect)

Description

[Hiroyuki Ikezoe (:hiro)]

We need a method which fires wheel events without flush just like synthesizeMouseAtPoint.

In out animation tests[1], we need to know whether various animations on various situations update its style or not.  EventUtils.synthesizeWheel calls getBoundingClientRect which leads style flush in it.  We need another method similar to synthesizeMouseAtPoint there.

[1] https://dxr.mozilla.org/mozilla-central/rev/66e07ef46853709e3fa91e7c9ad9fe6abf0d5f06/dom/animation/test/chrome/test_restyles.html

Comment 1

[Hiroyuki Ikezoe (:hiro)]

(In reply to Hiroyuki Ikezoe (:hiro) from comment #0)
> We need a method which fires wheel events without flush just like
> synthesizeMouseAtPoint.
> 
> In out animation tests[1], we need to know whether various animations on
> various situations update its style or not.  EventUtils.synthesizeWheel
> calls getBoundingClientRect which leads style flush in it.

The style flush comes from https://dxr.mozilla.org/mozilla-central/rev/66e07ef46853709e3fa91e7c9ad9fe6abf0d5f06/dom/base/Element.cpp#921

Comment 2

[Hiroyuki Ikezoe (:hiro)]

Attachment: MozReview Request: Bug 1241672 - Add synthesizeWheelAtPoint to avoid styling flush. r?smaug

Review commit: https://reviewboard.mozilla.org/r/31853/diff/#index_header
See other reviews: https://reviewboard.mozilla.org/r/31853/

Comment 3

[Olli Pettay [:smaug][[e-mail]]]

Comment on attachment 8710737 [details]
MozReview Request: Bug 1241672 - Add synthesizeWheelAtPoint to avoid styling flush. r?smaug

https://reviewboard.mozilla.org/r/31853/#review28585

::: testing/mochitest/tests/SimpleTest/EventUtils.js:410
(Diff revision 1)
> - * Synthesize a wheel event on a target. The actual client point is determined
> + * Synthesize a wheel event at a particular point in aWindow.

Want to document here that this method is trying to not flush layout. It is not too obvious without some comment.

Comment 4

[Hiroyuki Ikezoe (:hiro)]

Comment on attachment 8710737 [details]
MozReview Request: Bug 1241672 - Add synthesizeWheelAtPoint to avoid styling flush. r?smaug

Review request updated; see interdiff: https://reviewboard.mozilla.org/r/31853/diff/1-2/

Comment 5

[Hiroyuki Ikezoe (:hiro)]

https://treeherder.mozilla.org/#/jobs?repo=try&revision=646d4553d7da

Comment 6

[Pulsebot]

https://hg.mozilla.org/integration/mozilla-inbound/rev/c7b15445fa23

Comment 7

[Phil Ringnalda (:philor)]

https://hg.mozilla.org/mozilla-central/rev/c7b15445fa23