commit 798b5cdff6f50fa0d19a198f5f6e3f57425fbf05
author rune <rune@opera.com> Mon Aug 08 22:04:26 2016
committer Commit bot <commit-bot@chromium.org> Mon Aug 08 22:08:09 2016
tree 4955ef32b49b7268bfb1d61266fa9a0aee00cc10
parent 5822d6c9a8d83437964e171af05956b543b71689

Style invalidation support for :first/last/only-child.

Got rid of SubtreeStyleChanges for those pseudo classes. Also fixed
issue 245914 by looking at next/previous element, not node, to figure
out if we are the first. The code in checkForSiblingStyleChanges could
be restructured quite a bit and made simpler now have changedElement
(changedNode => changeElement since the input is always an element).

BUG=245914

Review-Url: https://codereview.chromium.org/2229503002
Cr-Commit-Position: refs/heads/master@{#410472}