[webkit-reviews] review granted: [Bug 226399] background-attachment:fixed inside position:fixed shouldn't cause slow scrolling : [Attachment 430309] Patch

[bugzilla-daemon at webkit.org]

Simon Fraser (smfr) <simon.fraser at apple.com> has granted Cameron McCormack
(:heycam) <heycam at apple.com>'s request for review:
Bug 226399: background-attachment:fixed inside position:fixed shouldn't cause
slow scrolling
https://bugs.webkit.org/show_bug.cgi?id=226399

Attachment 430309: Patch

https://bugs.webkit.org/attachment.cgi?id=430309&action=review




--- Comment #7 from Simon Fraser (smfr) <simon.fraser at apple.com> ---
Comment on attachment 430309
  --> https://bugs.webkit.org/attachment.cgi?id=430309
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=430309&action=review

Seems OK, but it's worrisome that some layout tests that don't have fixed
backgrounds have different repaint behavior.

> Source/WebCore/rendering/RenderLayerCompositor.cpp:4920
> +	       // scrolling tree propagates
DescendantScrollersHaveSynchronousScrolling bits up the
> +	       // tree, but shouldUpdateScrollLayerPositionSynchronously looks
at the scrolling state
> +	       // tree instead.)

Yeah that sucks.