1785103 - Chrome-only scrollend events are fired multiple times for one gesture

Status: RESOLVED FIXED

(Core :: Panning and Zooming, defect, P3)

Description

[Dan Robertson (:dlrobertson)]

Currently scrollend events are fired far more frequently than they should according to the spec. This happens because ScrollFrameHelper::ScrollToCSSPixelsForApz calls ScrollFrameHelper::ScrollToWithOrigin with the instant scroll option, which will cause the event to be fired here.

Comment 1

[Dan Robertson (:dlrobertson)]

Attachment: Bug 1785103 - Fire the scrollend event only once per gesture. r=botond,hiro

The scrollend event should only be fired once, at the very end of the gesture.
Fire the event for user gestures only on APZStateChange::eTransformEnd, which
is dispatched when APZ transitions from a transforming state to a state that
does not transform (e.g. a state change from PANNING to NOTHING).
CompleteAsyncScroll() should only post the scrollend event if the scroll was a
programmatic instant scroll.

Comment 2

[Dan Robertson (:dlrobertson)]

Attachment: Bug 1785103 - Move ScrollFrameHelper::SetTransformingByAPZ(() definition out-of-line. r=hiro,botond

Comment 3

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/2712b51e6b75
Move ScrollFrameHelper::SetTransformingByAPZ(() definition out-of-line. r=botond
https://hg.mozilla.org/integration/autoland/rev/0b1a9ad58327
Fire the scrollend event only once per gesture. r=botond,hiro

Comment 4

[Atila Butkovits]

Backed out for causing failures at test_group_scrollend.html.

Backout link: https://hg.mozilla.org/integration/autoland/rev/12ee4f90ec413104a8166e96545c2dea0a8e7659

Push with failrues: https://treeherder.mozilla.org/jobs?repo=autoland&resultStatus=testfailed%2Cbusted%2Cexception%2Cretry%2Cusercancel&revision=0b1a9ad58327e692889b628027c4e27e6cae4b28&selectedTaskRun=Qu7p25KTTTK8KRKrcZD-BQ.0

Failure log: https://treeherder.mozilla.org/logviewer?job_id=390238769&repo=autoland&lineNumber=6988

Comment 5

[Dan Robertson (:dlrobertson)]

Gah! I should have caught that. The test uses wheel scroll events, which are not supported by android. The test should be skipped for mobile.

Comment 6

[Atila Butkovits]

https://hg.mozilla.org/mozilla-central/rev/a7f54579d83a
https://hg.mozilla.org/mozilla-central/rev/db80d927147a