Bug 217718

Summary: Scrolls in the passive handler region should be reported as handled promptly
Product: WebKit Reporter: Simon Fraser (smfr) <simon.fraser>
Component: ScrollingAssignee: Simon Fraser (smfr) <simon.fraser>
Status: RESOLVED FIXED    
Severity: Normal CC: Hironori.Fujii, simon.fraser, thorton, 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 thorton: review+, ews-feeder: commit-queue-

Description Simon Fraser (smfr) 2020-10-14 11:08:38 PDT 
The WebContent process reports back to the UI process when events are handled (and for wheel events this is used to know if the page overrode history swipes, for example).

When handling wheel events in the passive event handler region, we should report that the scrolls are handled promptly to avoid the UI process queueing up events, which impacts scrolling performance.
Comment 1 Radar WebKit Bug Importer 2020-10-14 11:09:22 PDT 
<rdar://problem/70300104>
Comment 2 Simon Fraser (smfr) 2020-10-14 11:49:53 PDT 
Created attachment 411354 [details]
Patch
Comment 3 Simon Fraser (smfr) 2020-10-14 16:56:35 PDT 
https://bugs.webkit.org/show_bug.cgi?id=217718
Comment 4 Fujii Hironori 2020-10-18 13:27:33 PDT 
Filed: Bug 217850 – [WinCairo] sluggish page scrolling for wheel events since r268499