tree 64c56bbd0c83fd98dbdac9b2c035df5e6ca574e0
parent 6aed12316ecd85b6dfc91df5d7b07922e33be636
author zalan@apple.com <zalan@apple.com@268f45cc-cd09-0410-ab3c-d52691b4dbfc> 1463018999 +0000
committer zalan@apple.com <zalan@apple.com@268f45cc-cd09-0410-ab3c-d52691b4dbfc> 1463018999 +0000

Absolute positioned element is not placed properly when parent becomes the containing block.
https://bugs.webkit.org/show_bug.cgi?id=157455
<rdar://problem/26212568>

Reviewed by Simon Fraser.

When a container becomes a containing block, we need to check if there are any positioned boxes in its subtree
in order to "re-parent" them. It basically means that we remove them from RenderBlock::positionedDescendants map
and they'll get re-inserted during the next layout correctly.
This patch fixes the case when a container becomes the containing block by setting the transform property and its positioned
child gets misplaced.

Source/WebCore:

Test: fast/block/containing-block-changes.html

* rendering/RenderBlock.cpp:
(WebCore::RenderBlock::removePositionedObjectsIfNeeded):
(WebCore::RenderBlock::styleWillChange):
* rendering/RenderBlock.h:

LayoutTests:

* fast/block/containing-block-changes-expected.html: Added.
* fast/block/containing-block-changes.html: Added.

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@200736 268f45cc-cd09-0410-ab3c-d52691b4dbfc