Mark host for style recalc (and child recalc) whenever adding a ShadowRoot

Mark host for style recalc (and child recalc) whenever adding a ShadowRoot

We would forget to mark childNeedsStyleRecalc on the host when adding a
ShadowRoot and then if the host was display none never clear the bits
on the ShadowRoot which could result in wrong answers from
getComputedStyle.

Now we mark the bit and also mark the host immediately to ensure the dirty
bits are in a consistent state.

BUG=492730
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=196292

[esprehn, 2015-06-02 04:47:36]

esprehn@chromium.org changed reviewers:
+ hayato@chromium.org, timloh@chromium.org

[esprehn, 2015-06-02 04:47:40]

The CQ bit was checked by esprehn@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2015-06-02 04:50:57]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1151593005/20001

[hayato, 2015-06-02 04:56:28]

lgtm

[esprehn, 2015-06-02 04:58:20]

The CQ bit was unchecked by esprehn@chromium.org

[esprehn, 2015-06-02 04:58:22]

The CQ bit was checked by esprehn@chromium.org

[commit-bot: I haz the power, 2015-06-02 04:58:58]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1151593005/20001

[commit-bot: I haz the power, 2015-06-02 07:26:21]

Committed patchset #2 (id:20001) as
https://src.chromium.org/viewvc/blink?view=rev&revision=196292