[webkit-reviews] review requested: [Bug 95494] Make RenderLayer::usesCompositedScrolling scrollbars agnostic : [Attachment 179334] patch 4 - materialization of comment #20

[bugzilla-daemon at webkit.org]

Antonio Gomes <tonikitoo at webkit.org> has asked	for review:
Bug 95494: Make RenderLayer::usesCompositedScrolling scrollbars agnostic
https://bugs.webkit.org/show_bug.cgi?id=95494

Attachment 179334: patch 4 - materialization of comment #20
https://bugs.webkit.org/attachment.cgi?id=179334&action=review

------- Additional Comments from Antonio Gomes <tonikitoo at webkit.org>
Raising the r? flag, although Simon suggested a different path on IRC, for the
sake of this bug, querying if FrameView's scrollable area set cache (via
::containsScrollableArea) contains itself is enough, since
FrameView::m_scrollableAreaSet is updated after every layout from
RenderLayer::updateScrollbarsAfterLayout. 

That way, we are sure that the information gotten from
FrameView::containsScrollableArea is in accordance with the last complete
layout.

I can work on a follow up to convert this whole method to something similar to
what other ::requiresCompositingForXXX method do with regards to "pending
layout state".