Bug 106502

Summary: Don't drop to huge tile mode if we're only slow-scrolling because of a page overlay
Product: WebKit Reporter: Tim Horton <thorton>
Component: Layout and RenderingAssignee: Nobody <webkit-unassigned>
Status: RESOLVED FIXED    
Severity: Normal CC: andersca, bdakin, eric, ojan.autocc, simon.fraser, webkit.review.bot
Priority: P2 Keywords: InRadar
Version: 528+ (Nightly build)   
Hardware: Unspecified   
OS: Unspecified   
Attachments:
Description Flags
no giant tiles simon.fraser: review+

Description Tim Horton 2013-01-09 16:39:53 PST 
We only use the MainThreadScrollingReason "ForcedOnMainThread" if we install a page overlay (didInstallPageOverlay), which clients can do arbitrarily.

We probably should still use tile-sized tiles in this case (this will also prevent us from falling into gigantic tiles for WebKit2 find-in-page, among other things).
Comment 1 Simon Fraser (smfr) 2013-01-09 16:40:17 PST 
And the web inspector.
Comment 2 Tim Horton 2013-01-09 16:42:06 PST 
Created attachment 182012 [details]
no giant tiles
Comment 3 Anders Carlsson 2013-01-09 16:45:57 PST 
Comment on attachment 182012 [details]
no giant tiles

View in context: https://bugs.webkit.org/attachment.cgi?id=182012&action=review

> Source/WebCore/rendering/RenderLayerBacking.cpp:204
> -            if (scrollingCoordinator->shouldUpdateScrollLayerPositionOnMainThread())
> +            if (scrollingCoordinator->mainThreadScrollingReasons() & ~ScrollingCoordinator::ForcedOnMainThread)

I think you should explain what this does with a comment.
Comment 4 Tim Horton 2013-01-09 16:46:43 PST 
(In reply to comment #3)
> (From update of attachment 182012 [details])
> View in context: https://bugs.webkit.org/attachment.cgi?id=182012&action=review
> 
> > Source/WebCore/rendering/RenderLayerBacking.cpp:204
> > -            if (scrollingCoordinator->shouldUpdateScrollLayerPositionOnMainThread())
> > +            if (scrollingCoordinator->mainThreadScrollingReasons() & ~ScrollingCoordinator::ForcedOnMainThread)
> 
> I think you should explain what this does with a comment.

okiedokie.
Comment 5 Tim Horton 2013-01-09 16:51:52 PST 
<rdar://problem/12959143>
Comment 6 Tim Horton 2013-01-09 16:52:00 PST 
http://trac.webkit.org/changeset/139258