Fix crash when destory VRServiceImpl

Fix crash when destory VRServiceImpl

BUG=679108
Review-Url: https://codereview.chromium.org/2625373002
Cr-Commit-Position: refs/heads/master@{#443564}
Committed: https://chromium.googlesource.com/chromium/src/+/22123babbfad63ed9efaf934d804a163176d9421

[bshe, 2017-01-12 17:18:38]

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

[commit-bot: I haz the power, 2017-01-12 17:19:16]

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

[bshe, 2017-01-12 17:19:44]

bshe@chromium.org changed reviewers:
+ bajones@chromium.org

[bshe, 2017-01-12 17:19:44]

Hi Brandon. PTAL. thanks!

[commit-bot: I haz the power, 2017-01-12 18:07:08]

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

[commit-bot: I haz the power, 2017-01-12 18:07:08]

Dry run: This issue passed the CQ dry run.

[bajones, 2017-01-13 04:44:33]

On 2017/01/12 17:19:44, bshe wrote:
> Hi Brandon. PTAL. thanks!

LGTM

[bshe, 2017-01-13 15:45:12]

The CQ bit was checked by bshe@chromium.org

[commit-bot: I haz the power, 2017-01-13 15:45:36]

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, 2017-01-13 15:49:27]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1484322312645200, "parent_rev":
"9b8d527fa720a2b07a154134ec740b69f0622e90", "commit_rev":
"22123babbfad63ed9efaf934d804a163176d9421"}

[commit-bot: I haz the power, 2017-01-13 15:49:57]

Description was changed from

==========
Fix crash when destory VRServiceImpl

BUG=679108
==========

to

==========
Fix crash when destory VRServiceImpl

BUG=679108

Review-Url: https://codereview.chromium.org/2625373002
Cr-Commit-Position: refs/heads/master@{#443564}
Committed:
https://chromium.googlesource.com/chromium/src/+/22123babbfad63ed9efaf934d804...
==========

[commit-bot: I haz the power, 2017-01-13 15:49:58]

Committed patchset #1 (id:1) as
https://chromium.googlesource.com/chromium/src/+/22123babbfad63ed9efaf934d804...