Bug 217719

Summary: Scrolls in the passive event region only send one wheel event to the DOM
Product: WebKit Reporter: Simon Fraser (smfr) <simon.fraser>
Component: ScrollingAssignee: Simon Fraser (smfr) <simon.fraser>
Status: RESOLVED FIXED    
Severity: Normal CC: cmarcelo, ews-watchlist, fred.wang, jamesr, luiz, simon.fraser, thorton, tonikitoo, webkit-bug-importer
Priority: P2 Keywords: InRadar
Version: Safari Technology Preview   
Hardware: Unspecified   
OS: Unspecified   
See Also: https://bugs.webkit.org/show_bug.cgi?id=158439
Attachments:
Description Flags
Patch none

Description Simon Fraser (smfr) 2020-10-14 11:10:28 PDT 
When the scrolling thread latches on a node (which might be in the passive event listener region), we should also store the processing steps and used them for latched scrolls. If we don't, then we would hit-test the layers again, and potentially get a different answer (breaking the rules of latching).

Also latched scrolls need to use WheelEventProcessingSteps::MainThreadForDOMEventDispatch if in the passive region.
Comment 1 Radar WebKit Bug Importer 2020-10-14 11:11:04 PDT 
<rdar://problem/70300204>
Comment 2 Simon Fraser (smfr) 2020-10-15 11:11:13 PDT 
Created attachment 411464 [details]
Patch
Comment 3 EWS 2020-10-15 12:24:46 PDT 
Committed r268544: <https://trac.webkit.org/changeset/268544>

All reviewed patches have been landed. Closing bug and clearing flags on attachment 411464 [details].