Add a comment to caution that timer::stop() should not be called too much

Add a comment to caution that timer::stop() should not be called too much

As requested by kinuko-san in https://codereview.chromium.org/2124693002/

BUG=

Committed: https://crrev.com/b2d65acc7b0d61ff6c8a4121b9952fb77c16c121
Cr-Commit-Position: refs/heads/master@{#414007}

[haraken, 2016-08-24 05:57:19]

haraken@chromium.org changed reviewers:
+ kinuko@chromium.org, nhiroki@chromium.org

[haraken, 2016-08-24 05:57:19]

nhiroki@: PTAL

[nhiroki, 2016-08-24 05:59:14]

lgtm

[haraken, 2016-08-24 05:59:44]

The CQ bit was checked by haraken@chromium.org

[commit-bot: I haz the power, 2016-08-24 06:00:07]

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, 2016-08-24 07:38:39]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-08-24 07:40:21]

Description was changed from

==========
Add a comment to caution that timer::stop() should not be called too much

As requested by kinuko-san in https://codereview.chromium.org/2124693002/

BUG=
==========

to

==========
Add a comment to caution that timer::stop() should not be called too much

As requested by kinuko-san in https://codereview.chromium.org/2124693002/

BUG=

Committed: https://crrev.com/b2d65acc7b0d61ff6c8a4121b9952fb77c16c121
Cr-Commit-Position: refs/heads/master@{#414007}
==========

[commit-bot: I haz the power, 2016-08-24 07:40:21]

Patchset 1 (id:??) landed as
https://crrev.com/b2d65acc7b0d61ff6c8a4121b9952fb77c16c121
Cr-Commit-Position: refs/heads/master@{#414007}