Maintain child dependent ComputedStyle flags if propagation stops.

Maintain child dependent ComputedStyle flags if propagation stops.

There are two non-inherited flags in ComputedStyle which may be set as a
result of calculating the computed style of one of its descendants. Those
are the empty state flag, and the explicit inheritance flag. r190990
optimized propagation of inherited properties, but the mentioned flags
were not properly set if the propagation stopped at an element which had
children that would set these flags.

If a child-dependent flag is set in the old style, and there is no need
to inherit properties, and no children which needs a style recalc, copy
the flags from the old to the new ComputedStyle.

If there is no need to inherit properties, but some child needs a style
recalc, return Inherit to re-compute the child-dependent flags from its
children.

R=timloh@chromium.org,esprehn@chromium.org
BUG=487216
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=195462

[rune, 2015-05-15 12:42:09]

rune@opera.com changed reviewers:
+ dstockwell@chromium.org, eae@chromium.org

[rune, 2015-05-15 12:42:09]

P1 release-block-stable.

[Timothy Loh, 2015-05-18 10:05:33]

On 2015/05/15 12:42:09, rune wrote:
> P1 release-block-stable.

lgtm, sorry for the delay

[rune, 2015-05-18 10:29:12]

The CQ bit was checked by rune@opera.com

[commit-bot: I haz the power, 2015-05-18 10:29:26]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1133263003/1

[commit-bot: I haz the power, 2015-05-18 12:02:50]

Committed patchset #1 (id:1) as
https://src.chromium.org/viewvc/blink?view=rev&revision=195462