Bug 58539

Summary: WebKit1's WebView sometimes does some extra work when a layout-before-paint puts the page into accelerated compositing mode
Product: WebKit Reporter: Adam Roben (:aroben) <aroben>
Component: Layout and RenderingAssignee: Nobody <webkit-unassigned>
Status: NEW ---    
Severity: Normal Keywords: PlatformOnly
Priority: P2    
Version: 528+ (Nightly build)   
Hardware: PC   
OS: Windows 7   

Description Adam Roben (:aroben) 2011-04-14 06:49:07 PDT
Whenever WebView is about to paint, it first does a layout to ensure it's painting up-to-date bits. This layout can put the page into accelerated compositing mode. But WebView doesn't detect that this has happened, and goes ahead and finishes the paint anyway, even though the painted bits will never be seen (since now rendering is being taken care of by the layer tree host).

It would be somewhat more efficient for WebView to detect that this has happened and bail out of the paint.