Remove some unused linked_ptr.h includes in c/b/extensions/api

Remove some unused linked_ptr.h includes in c/b/extensions/api

BUG=556939
Test=None

Committed: https://crrev.com/b65b322f74351da8b61fe35889348649b56d213d
Cr-Commit-Position: refs/heads/master@{#416161}

[lazyboy, 2016-09-02 00:36:28]

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

[commit-bot: I haz the power, 2016-09-02 00:36:49]

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

[lazyboy, 2016-09-02 00:37:20]

lazyboy@chromium.org changed reviewers:
+ rdevlin.cronin@chromium.org

[lazyboy, 2016-09-02 00:37:21]

Hi, a tiny codereview for you, thanks.

[Devlin, 2016-09-02 00:55:22]

lgtm!

[commit-bot: I haz the power, 2016-09-02 01:38:53]

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

[commit-bot: I haz the power, 2016-09-02 01:38:54]

Dry run: This issue passed the CQ dry run.

[lazyboy, 2016-09-02 01:45:43]

The CQ bit was checked by lazyboy@chromium.org

[commit-bot: I haz the power, 2016-09-02 01:46:05]

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 01:49:51]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-09-02 01:51:21]

Description was changed from

==========
Remove some unused linked_ptr.h includes in c/b/extensions/api

BUG=556939
Test=None
==========

to

==========
Remove some unused linked_ptr.h includes in c/b/extensions/api

BUG=556939
Test=None

Committed: https://crrev.com/b65b322f74351da8b61fe35889348649b56d213d
Cr-Commit-Position: refs/heads/master@{#416161}
==========

[commit-bot: I haz the power, 2016-09-02 01:51:22]

Patchset 1 (id:??) landed as
https://crrev.com/b65b322f74351da8b61fe35889348649b56d213d
Cr-Commit-Position: refs/heads/master@{#416161}