Add support for deleting history.

Add support for deleting history.

BUG=693633
Review-Url: https://codereview.chromium.org/2720753003
Cr-Commit-Position: refs/heads/master@{#453727}
Committed: https://chromium.googlesource.com/chromium/src/+/4e0d26ac80d31bbfa773948f61122c635c5487f4

[dproctor, 2017-02-28 18:38:22]

Description was changed from

==========
Add support for deleting history.

BUG=693633
==========

to

==========
Add support for deleting history.

BUG=693633
==========

[dproctor, 2017-02-28 18:38:22]

dproctor@google.com changed reviewers:
+ mariakhomenko@chromium.org, wychen@chromium.org

[Maria, 2017-02-28 20:07:50]

lgtm

[dproctor, 2017-02-28 21:19:34]

The CQ bit was checked by dproctor@google.com to run a CQ dry run

[commit-bot: I haz the power, 2017-02-28 21:20:34]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[dproctor, 2017-02-28 21:20:48]

The CQ bit was checked by dproctor@google.com

[commit-bot: I haz the power, 2017-02-28 21:21:16]

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, 2017-02-28 22:20:09]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1488316848289510, "parent_rev":
"fe4c57f8d526e1c286d0504f40e5b178cc527e6c", "commit_rev":
"4e0d26ac80d31bbfa773948f61122c635c5487f4"}

[commit-bot: I haz the power, 2017-02-28 22:20:45]

Description was changed from

==========
Add support for deleting history.

BUG=693633
==========

to

==========
Add support for deleting history.

BUG=693633

Review-Url: https://codereview.chromium.org/2720753003
Cr-Commit-Position: refs/heads/master@{#453727}
Committed:
https://chromium.googlesource.com/chromium/src/+/4e0d26ac80d31bbfa773948f6112...
==========

[commit-bot: I haz the power, 2017-02-28 22:20:46]

Committed patchset #1 (id:1) as
https://chromium.googlesource.com/chromium/src/+/4e0d26ac80d31bbfa773948f6112...