tree df700c1355ec60a76c7ad27098ece80a9dffe467
parent 8cef920bdae4a11dc1205ae50645f57ea479aa48
author simon.fraser@apple.com <simon.fraser@apple.com@268f45cc-cd09-0410-ab3c-d52691b4dbfc> 1566699270 +0000
committer simon.fraser@apple.com <simon.fraser@apple.com@268f45cc-cd09-0410-ab3c-d52691b4dbfc> 1566699270 +0000

Have RenderLayer::calculateClipRects() use offsetFromAncestor() when possible
https://bugs.webkit.org/show_bug.cgi?id=201066

Reviewed by Dean Jackson.

offsetFromAncestor() is a layer tree walk, so faster than localToContainerPoint(),
but we can't use it when there are transforms on the layer and intermediates up
to the ancestor.

canUseConvertToLayerCoords() was trying to answer the question about whether it's
OK to use offsetFromAncestor() (which calls convertToLayerCoords() internally), but
it has insufficient information to make a determination. Leave this issue alone, but
at least rename canUseConvertToLayerCoords().

* rendering/RenderLayer.cpp:
(WebCore::RenderLayer::updateLayerPositions):
(WebCore::RenderLayer::calculateClipRects const):
* rendering/RenderLayer.h:


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@249091 268f45cc-cd09-0410-ab3c-d52691b4dbfc