Move documentation of base::Callback from base/callback.h to docs/callback.md

Move documentation of base::Callback from base/callback.h to docs/callback.md

BUG=554299
Committed: https://crrev.com/703f156dc15c925f88a1b9df181652f26fbf64c6
Cr-Commit-Position: refs/heads/master@{#416208}

[tzik, 2016-09-02 04:45:14]

Description was changed from

==========
Move and update documentation on base/callback.h

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

to

==========
Move documentation of base::Callback from base/callback.h to docs/callback.md

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

[tzik, 2016-09-02 04:48:04]

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

[tzik, 2016-09-02 04:48:05]

PTAL

[tzik, 2016-09-02 04:49:01]

Description was changed from

==========
Move documentation of base::Callback from base/callback.h to docs/callback.md

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

to

==========
Move documentation of base::Callback from base/callback.h to docs/callback.md

BUG=554299
==========

[dcheng, 2016-09-02 05:07:22]

LGTM

[tzik, 2016-09-02 05:37:34]

The CQ bit was checked by tzik@chromium.org

[commit-bot: I haz the power, 2016-09-02 05:37:44]

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, 2016-09-02 07:37:12]

Description was changed from

==========
Move documentation of base::Callback from base/callback.h to docs/callback.md

BUG=554299
==========

to

==========
Move documentation of base::Callback from base/callback.h to docs/callback.md

BUG=554299
==========

[commit-bot: I haz the power, 2016-09-02 07:37:18]

Committed patchset #4 (id:60001)

[commit-bot: I haz the power, 2016-09-02 07:39:08]

Description was changed from

==========
Move documentation of base::Callback from base/callback.h to docs/callback.md

BUG=554299
==========

to

==========
Move documentation of base::Callback from base/callback.h to docs/callback.md

BUG=554299

Committed: https://crrev.com/703f156dc15c925f88a1b9df181652f26fbf64c6
Cr-Commit-Position: refs/heads/master@{#416208}
==========

[commit-bot: I haz the power, 2016-09-02 07:39:09]

Patchset 4 (id:??) landed as
https://crrev.com/703f156dc15c925f88a1b9df181652f26fbf64c6
Cr-Commit-Position: refs/heads/master@{#416208}