[Extensions] Make ExtensionAPI use unique_ptrs instead of linked_ptrs

[Extensions] Make ExtensionAPI use unique_ptrs instead of linked_ptrs

For the SchemaMap, use unique_ptrs instead of linked_ptrs. Also clean
up the implementation a little.

BUG=None

Committed: https://crrev.com/6bf3cc8e81efd9ba28435a5aa53d06b5a439b03f
Cr-Commit-Position: refs/heads/master@{#412688}

[Devlin, 2016-08-17 22:08:52]

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

[commit-bot: I haz the power, 2016-08-17 22:09:11]

Dry run: 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, 2016-08-17 22:53:24]

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

[commit-bot: I haz the power, 2016-08-17 22:53:25]

Dry run: Try jobs failed on following builders:
  linux_chromium_chromeos_ozone_rel_ng on master.tryserver.chromium.linux
(JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)

[Devlin, 2016-08-17 22:55:11]

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

[lazyboy, 2016-08-17 23:02:15]

lgtm

[Devlin, 2016-08-17 23:05:23]

The CQ bit was checked by rdevlin.cronin@chromium.org

[commit-bot: I haz the power, 2016-08-17 23:06:01]

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, 2016-08-17 23:24:15]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-08-17 23:35:31]

Description was changed from

==========
[Extensions] Make ExtensionAPI use unique_ptrs instead of linked_ptrs

For the SchemaMap, use unique_ptrs instead of linked_ptrs. Also clean
up the implementation a little.

BUG=None
==========

to

==========
[Extensions] Make ExtensionAPI use unique_ptrs instead of linked_ptrs

For the SchemaMap, use unique_ptrs instead of linked_ptrs. Also clean
up the implementation a little.

BUG=None

Committed: https://crrev.com/6bf3cc8e81efd9ba28435a5aa53d06b5a439b03f
Cr-Commit-Position: refs/heads/master@{#412688}
==========

[commit-bot: I haz the power, 2016-08-17 23:35:32]

Patchset 1 (id:??) landed as
https://crrev.com/6bf3cc8e81efd9ba28435a5aa53d06b5a439b03f
Cr-Commit-Position: refs/heads/master@{#412688}