Minimal feature collector for select selectors.

Minimal feature collector for select selectors.

Use a feature collector method that collects necessary features for select
attribute selectors. These selectors can only have element, id, class,
attribute and :not() according to the spec, and no combinators. Blink also
supports pseudo classes for UA shadow DOM.

A motivation here is to be able to collapse
RuleFeatureSet::collectFeaturesFromSelector into the same loop as
updateInvalidationSets now that invalidation sets are always in use.

R=chrishtr@chromium.org,esprehn@chromium.org

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=182755

[rune, 2014-09-24 23:16:00]

Patch on top of https://codereview.chromium.org/598093005

[esprehn, 2014-09-26 04:03:44]

lgtm

[rune, 2014-09-26 10:01:51]

The CQ bit was checked by rune@opera.com

[commit-bot: I haz the power, 2014-09-26 10:02:03]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/600223002/1

[commit-bot: I haz the power, 2014-09-26 11:07:17]

Committed patchset #1 (id:1) as 182755