Revert "Reverting custom pseudo element".

Revert "Reverting custom pseudo element".

This is not the same as a patch for just reverting r164153.
To make a patch smaller,
- Element IDL does not have webkitPseudo (not reverted).
- pseudo() invokes shadowPseudoId() (the old code uses pseudo() in shadowPseudoId()).
- setPseudo() also invokes setShadowPseudoId().

c.f. https://src.chromium.org/viewvc/blink?revision=164153&view=revision

BUG=349144
TEST=fast/dom/shadow/pseudo-attribute-rendering.html,fast/dom/shadow/styling-pseudo-attribute.html,fast/dom/shadow/shadow-pseudo-id.html,fast/dom/shadow/pseudo-attribute.html,fast/dom/shadow/styling-pseudo-attribute-in-shadow.html,fast/dom/shadow/shadow-nested-pseudo-id.html,fast/dom/shadow/custom-pseudo-in-selector-api.html,fast/dom/shadow/pseudo-attribute-dynamic.html

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=168627

[dglazkov, 2014-03-05 17:01:55]

+esprehn

[dglazkov, 2014-03-05 23:08:40]

lgtm

[esprehn, 2014-03-05 23:13:10]

lgtm, lets just make sure we revert this asap after we merge.

[tasak, 2014-03-06 06:24:15]

The CQ bit was checked by tasak@google.com

[commit-bot: I haz the power, 2014-03-06 06:24:28]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/tasak@google.com/187573002/1

[commit-bot: I haz the power, 2014-03-06 06:24:46]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2014-03-06 06:24:46]

Try jobs failed on following builders: linux_blink, win_blink_rel

[tasak, 2014-03-06 09:09:18]

The CQ bit was checked by tasak@google.com

[commit-bot: I haz the power, 2014-03-06 09:09:33]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/tasak@google.com/187573002/1

[commit-bot: I haz the power, 2014-03-06 09:58:33]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2014-03-06 09:58:33]

Try jobs failed on following builders: win_blink_rel

[tasak, 2014-03-06 11:52:34]

The CQ bit was checked by tasak@google.com

[commit-bot: I haz the power, 2014-03-06 11:52:50]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/tasak@google.com/187573002/1

[commit-bot: I haz the power, 2014-03-06 11:53:37]

Change committed as 168627