Fix ancestor check

Fix ancestor check

Before, for the common case that the actual_merge_base was already set
as base, the check for is_ancestor(base, actual_merge_base) would have
caused the base to be re-set.
This is a writing operation, which causes trouble e.g. for the parallel
operation of 'git cl status'.

R=iannucci@chromium.org, tandrii@chromium.org
BUG=

Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=300003

[Clemens Hammacher, 2016-04-15 15:14:15]

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

[commit-bot: I haz the power, 2016-04-15 15:14:20]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1888213004/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1888213004/1

[commit-bot: I haz the power, 2016-04-15 15:14:21]

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

[commit-bot: I haz the power, 2016-04-15 15:14:22]

Dry run: No L-G-T-M from a valid reviewer yet. 
CQ run can only be started by full committers or once the patch has
received an L-G-T-M from a full committer.
Even if an L-G-T-M may have been provided, it was from a non-committer,
_not_ a full super star committer.
Committers are members of the group "project-infra-committers".
Note that this has nothing to do with OWNERS files.

[iannucci, 2016-04-18 22:10:03]

lgtm

[iannucci, 2016-04-18 22:10:18]

On 2016/04/18 at 22:10:03, iannucci wrote:
> lgtm

(CQ should work too)

[Clemens Hammacher, 2016-04-19 07:54:11]

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

[commit-bot: I haz the power, 2016-04-19 07:54:17]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1888213004/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1888213004/1

[commit-bot: I haz the power, 2016-04-19 07:57:07]

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

[commit-bot: I haz the power, 2016-04-19 07:57:08]

Dry run: This issue passed the CQ dry run.

[Clemens Hammacher, 2016-04-19 08:37:09]

The CQ bit was checked by clemensh@chromium.org

[commit-bot: I haz the power, 2016-04-19 08:37:20]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1888213004/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1888213004/1

[commit-bot: I haz the power, 2016-04-19 08:39:56]

Description was changed from

==========
Fix ancestor check

Before, for the common case that the actual_merge_base was already set
as base, the check for is_ancestor(base, actual_merge_base) would have
caused the base to be re-set.
This is a writing operation, which causes trouble e.g. for the parallel
operation of 'git cl status'.

R=iannucci@chromium.org, tandrii@chromium.org
BUG=
==========

to

==========
Fix ancestor check

Before, for the common case that the actual_merge_base was already set
as base, the check for is_ancestor(base, actual_merge_base) would have
caused the base to be re-set.
This is a writing operation, which causes trouble e.g. for the parallel
operation of 'git cl status'.

R=iannucci@chromium.org, tandrii@chromium.org
BUG=

Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=300003
==========

[commit-bot: I haz the power, 2016-04-19 08:39:57]

Committed patchset #1 (id:1) as
http://src.chromium.org/viewvc/chrome?view=rev&revision=300003