Bug 192284

Summary:	EditorState code triggers additional layer flushes
Product:	WebKit	Reporter:	Simon Fraser (smfr) <simon.fraser>
Component:	HTML Editing	Assignee:	Nobody <webkit-unassigned>
Status:	NEW ---
Severity:	Normal	CC:	ap, rniwa, simon.fraser, wenson_hsieh
Priority:	P2
Version:	WebKit Nightly Build
Hardware:	Unspecified
OS:	Unspecified

Description Simon Fraser (smfr) 2018-12-01 20:58:47 PST

There are two code paths that trigger compositing layer flushes that would otherwise not happen; this may cause extra painting, which has a perf cost.

They are WebPage::sendPartialEditorStateAndSchedulePostLayoutUpdate() and WebPage::sendEditorStateUpdate(). I see these get called when running this Speedometer subtest:

http://browserbench.org/Speedometer2.0/?suite=VueJS-TodoMVC&iterationCount=100