[Sync] Remove !frontend_ checks in SBHI.

[Sync] Remove !frontend_ checks in SBHI.

All these functions are called from SyncBackendHostCore using a WeakHandle,
and we invalidate WeakPtrs during shutdown before nulling out the frontend_
pointer, so they aren't necessary.

BUG=669967
Committed: https://crrev.com/1bbc6856145b3e8e2984c9f7bef9261094e8fc9f
Cr-Commit-Position: refs/heads/master@{#435955}

[maxbogue, 2016-12-02 01:57:38]

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

[commit-bot: I haz the power, 2016-12-02 01:58:10]

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, 2016-12-02 03:04:40]

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

[commit-bot: I haz the power, 2016-12-02 03:04:40]

Dry run: This issue passed the CQ dry run.

[maxbogue, 2016-12-02 16:45:56]

maxbogue@chromium.org changed reviewers:
+ skym@chromium.org

[maxbogue, 2016-12-02 16:45:56]

PTAL!

[skym, 2016-12-02 16:47:24]

lgtm

[maxbogue, 2016-12-02 16:47:37]

The CQ bit was checked by maxbogue@chromium.org

[commit-bot: I haz the power, 2016-12-02 16:48:15]

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, 2016-12-02 16:51:47]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1480697257013220, "parent_rev":
"91171e06924fc21a6ebc53cbf0b195d5930c5a45", "commit_rev":
"7ccbe223b448ad476c69f13ef8f8213d89348545"}

[commit-bot: I haz the power, 2016-12-02 16:52:12]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-12-02 16:55:08]

Description was changed from

==========
[Sync] Remove !frontend_ checks in SBHI.

All these functions are called from SyncBackendHostCore using a WeakHandle,
and we invalidate WeakPtrs during shutdown before nulling out the frontend_
pointer, so they aren't necessary.

BUG=669967
==========

to

==========
[Sync] Remove !frontend_ checks in SBHI.

All these functions are called from SyncBackendHostCore using a WeakHandle,
and we invalidate WeakPtrs during shutdown before nulling out the frontend_
pointer, so they aren't necessary.

BUG=669967

Committed: https://crrev.com/1bbc6856145b3e8e2984c9f7bef9261094e8fc9f
Cr-Commit-Position: refs/heads/master@{#435955}
==========

[commit-bot: I haz the power, 2016-12-02 16:55:09]

Patchset 1 (id:??) landed as
https://crrev.com/1bbc6856145b3e8e2984c9f7bef9261094e8fc9f
Cr-Commit-Position: refs/heads/master@{#435955}