Deprecate step timing with position 'middle'

Deprecate step timing with position 'middle'

This patch adds a deprecation warning and UseCounter for instances of
the step animation timing function with step position 'middle' and the
keyword 'step-middle'.

This patch also adds a dummy document to TimingInputTest in order to
maintain the invariant that if step-middle is allowed then a non-null
Document* is provided for the UseCounter.

BUG=646265
Review-Url: https://codereview.chromium.org/2927123005
Cr-Commit-Position: refs/heads/master@{#478914}
Committed: https://chromium.googlesource.com/chromium/src/+/4cd8966bc2b20f69b9b23d2538eb25452775134e

[suzyh_UTC10 (ex-contributor), 2017-06-09 05:27:03]

suzyh@chromium.org changed reviewers:
+ ericwilligers@chromium.org

[Eric Willigers, 2017-06-09 06:10:11]

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

[Eric Willigers, 2017-06-09 06:10:21]

lgtm

[commit-bot: I haz the power, 2017-06-09 06:10:21]

Dry run: CQ is trying da patch.

Follow status at:
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2017-06-09 08:30:17]

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

[commit-bot: I haz the power, 2017-06-09 08:30:18]

Dry run: Try jobs failed on following builders:
  linux_chromium_rel_ng on master.tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)

[suzyh_UTC10 (ex-contributor), 2017-06-13 00:35:49]

suzyh@chromium.org changed reviewers:
+ dcheng@chromium.org

[suzyh_UTC10 (ex-contributor), 2017-06-13 00:38:00]

+dcheng for core/frame and public/platform OWNERS

I made a mistake during rebase, but I think I've fixed it up. Main difference to
patch 1 should be adding the counter to WebFeature.h instead of
UseCounterFeature.def. ericwilligers: Would you mind doing a quick sanity-check
that it all still looks good?

[Eric Willigers, 2017-06-13 00:44:10]

> Would you mind doing a quick sanity-check
that it all still looks good?

done, still lgtm

[dcheng, 2017-06-13 04:59:24]

lgtm

[suzyh_UTC10 (ex-contributor), 2017-06-13 04:59:59]

The CQ bit was checked by suzyh@chromium.org

[commit-bot: I haz the power, 2017-06-13 05:00:21]

CQ is trying da patch.

Follow status at:
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2017-06-13 06:37:25]

CQ is committing da patch.

Bot data: {"patchset_id": 20001, "attempt_start_ts": 1497329999807790,
"parent_rev": "a01ec54e907dcda55f339330da7c05149295131b", "commit_rev":
"4cd8966bc2b20f69b9b23d2538eb25452775134e"}

[commit-bot: I haz the power, 2017-06-13 06:37:35]

Description was changed from

==========
Deprecate step timing with position 'middle'

This patch adds a deprecation warning and UseCounter for instances of
the step animation timing function with step position 'middle' and the
keyword 'step-middle'.

This patch also adds a dummy document to TimingInputTest in order to
maintain the invariant that if step-middle is allowed then a non-null
Document* is provided for the UseCounter.

BUG=646265
==========

to

==========
Deprecate step timing with position 'middle'

This patch adds a deprecation warning and UseCounter for instances of
the step animation timing function with step position 'middle' and the
keyword 'step-middle'.

This patch also adds a dummy document to TimingInputTest in order to
maintain the invariant that if step-middle is allowed then a non-null
Document* is provided for the UseCounter.

BUG=646265

Review-Url: https://codereview.chromium.org/2927123005
Cr-Commit-Position: refs/heads/master@{#478914}
Committed:
https://chromium.googlesource.com/chromium/src/+/4cd8966bc2b20f69b9b23d2538eb...
==========

[commit-bot: I haz the power, 2017-06-13 06:37:37]

Committed patchset #2 (id:20001) as
https://chromium.googlesource.com/chromium/src/+/4cd8966bc2b20f69b9b23d2538eb...