DevTools: [CSS] getMatchedStylesForNode should return styles inherited through shadow boundary

DevTools: [CSS] getMatchedStylesForNode should return styles inherited through shadow boundary

The spec declares (article 7 at http://www.w3.org/TR/2012/WD-shadow-dom-20120522/):
    "the styles of the shadow host are inherited by the children of
    the shadow root"

This patch makes CSS.getMatchedStylesForNode comply with spec.

BUG=500915
R=pfeldman, dgozman

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=197366

[lushnikov, 2015-06-17 22:37:10]

ptal

[pfeldman, 2015-06-18 06:46:30]

lgtm

[lushnikov, 2015-06-18 10:24:52]

The CQ bit was checked by lushnikov@chromium.org

[commit-bot: I haz the power, 2015-06-18 10:25:05]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1182483004/20001

[commit-bot: I haz the power, 2015-06-18 11:54:01]

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

[commit-bot: I haz the power, 2015-06-18 11:54:02]

Try jobs failed on following builders:
  linux_blink_rel on tryserver.blink (JOB_FAILED,
http://build.chromium.org/p/tryserver.blink/builders/linux_blink_rel/builds/6...)

[lushnikov, 2015-06-18 15:11:20]

The CQ bit was checked by lushnikov@chromium.org

[lushnikov, 2015-06-18 15:11:21]

The patchset sent to the CQ was uploaded after l-g-t-m from
pfeldman@chromium.org
Link to the patchset: https://codereview.chromium.org/1182483004/#ps40001
(title: "rebaseline")

[commit-bot: I haz the power, 2015-06-18 15:11:42]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1182483004/40001

[commit-bot: I haz the power, 2015-06-18 16:33:24]

Committed patchset #3 (id:40001) as
https://src.chromium.org/viewvc/blink?view=rev&revision=197366