Remove tabStop feature

Remove tabStop feature

This feature will retire in favor of new 'delegatesFocus'
property on shadow roots.

This CL removes all the code related to 'tabStop' feature
as well as its RuntimeEnabledFeatures, UseCounters
(TabStopProperty, TabStopAttribute), and its layout tests.

BUG=380445, 496005
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=196726

[kochi, 2015-06-08 04:52:37]

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

[kochi, 2015-06-08 05:52:50]

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

[commit-bot: I haz the power, 2015-06-08 05:52:57]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1144953007/60001

[kochi, 2015-06-08 06:03:30]

PTAL

[hayato, 2015-06-08 06:51:43]

lgtm

[commit-bot: I haz the power, 2015-06-08 07:24:18]

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

[commit-bot: I haz the power, 2015-06-08 07:24:19]

Dry run: This issue passed the CQ dry run.

[kochi, 2015-06-08 07:25:43]

The CQ bit was checked by kochi@chromium.org

[commit-bot: I haz the power, 2015-06-08 07:25:58]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1144953007/60001

[commit-bot: I haz the power, 2015-06-08 07:32:56]

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

[commit-bot: I haz the power, 2015-06-08 07:32:58]

Try jobs failed on following builders:
  blink_presubmit on tryserver.blink (JOB_FAILED,
http://build.chromium.org/p/tryserver.blink/builders/blink_presubmit/builds/3...)

[kochi, 2015-06-09 01:00:46]

kochi@chromium.org changed reviewers:
+ tkent@chromium.org

[kochi, 2015-06-09 01:01:06]

tkent-san,
Could you review for RuntimeEnabledFeatures.in?

[tkent, 2015-06-09 01:05:48]

> (TabStopProperty, TabStopAttribute - definitions will stay),

Why do you keep them?

[kochi, 2015-06-09 01:18:56]

On 2015/06/09 01:05:48, tkent wrote:
> > (TabStopProperty, TabStopAttribute - definitions will stay),
> 
> Why do you keep them?

I was wondering if removing the definition will cause "unknown" counters
will be sent from existing dev/beta users, stat counter might confused.

As long as I glanced at the log of UseCounter.h, it seems obsolete
counters have been regularly removed and at least for these counters,
they won't make much sense after this CL lands, so I think it is okay
to remove them.

Removed use counters, rebased, and updated the description.

[tkent, 2015-06-09 01:20:52]

The CQ bit was checked by tkent@chromium.org

[tkent, 2015-06-09 01:20:53]

lgtm

[tkent, 2015-06-09 01:20:53]

The patchset sent to the CQ was uploaded after l-g-t-m from hayato@chromium.org
Link to the patchset: https://codereview.chromium.org/1144953007/#ps100001
(title: "rebase")

[commit-bot: I haz the power, 2015-06-09 01:21:40]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1144953007/100001

[commit-bot: I haz the power, 2015-06-09 03:00:45]

Committed patchset #6 (id:100001) as
https://src.chromium.org/viewvc/blink?view=rev&revision=196726