Bug 210438

Summary: [Async overflow scroll] Custom scrollbars on gmail don't show
Product: WebKit Reporter: Simon Fraser (smfr) <simon.fraser>
Component: ScrollingAssignee: Simon Fraser (smfr) <simon.fraser>
Status: RESOLVED FIXED    
Severity: Normal CC: esprehn+autocc, ews-watchlist, fred.wang, glenn, kondapallykalyan, pdr, simon.fraser, thorton, webkit-bug-importer
Priority: P2 Keywords: InRadar
Version: Safari Technology Preview   
Hardware: Unspecified   
OS: Unspecified   
Bug Depends on: 210460    
Bug Blocks:    
Attachments:
Description Flags
Reduction
none
Patch
thorton: review+
Patch
none
Patch none

Description Simon Fraser (smfr) 2020-04-13 10:19:18 PDT
Created attachment 396302 [details]
Reduction

With async overflow scrolling enabled, the custom scrollbars on gmail are missing.
Comment 1 Radar WebKit Bug Importer 2020-04-13 10:19:47 PDT
<rdar://problem/61722541>
Comment 2 Radar WebKit Bug Importer 2020-04-13 10:19:49 PDT
<rdar://problem/61722545>
Comment 3 Simon Fraser (smfr) 2020-04-13 11:29:31 PDT
This happens any time we don't make backing store for the scroller; custom scrollbars are currently just painted.
Comment 4 Simon Fraser (smfr) 2020-04-13 16:21:13 PDT
Created attachment 396355 [details]
Patch
Comment 5 Tim Horton 2020-04-13 16:23:03 PDT
Comment on attachment 396355 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=396355&action=review

> Source/WebCore/rendering/RenderLayerBacking.cpp:1791
>  bool RenderLayerBacking::requiresHorizontalScrollbarLayer() const

These functions seem a bit needless now. But maybe they're used externally?
Comment 6 Simon Fraser (smfr) 2020-04-13 18:06:30 PDT
Created attachment 396366 [details]
Patch
Comment 7 Simon Fraser (smfr) 2020-04-13 21:45:10 PDT
This is waiting on bug 210460.
Comment 8 Simon Fraser (smfr) 2020-04-13 23:11:17 PDT
Created attachment 396382 [details]
Patch
Comment 9 EWS 2020-04-14 09:04:26 PDT
Committed r260074: <https://trac.webkit.org/changeset/260074>

All reviewed patches have been landed. Closing bug and clearing flags on attachment 396382 [details].