Update {virtual,override,final} to follow C++11 style in sandbox, round 2.

Update {virtual,override,final} to follow C++11 style in sandbox, round 2.

The Google style guide states that only one of {virtual,override,final}
should be used for each declaration, since override implies virtual and
final implies both virtual and override.

This patch was automatically generated with a ChromeOS build using a
variation of https://codereview.chromium.org/598073004.

BUG=417463
Committed: https://crrev.com/ee9fd750d987501be2d167ebe602333dfa19458c
Cr-Commit-Position: refs/heads/master@{#312745}

[dcheng, 2015-01-22 22:38:22]

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

[Jorge Lucangeli Obes, 2015-01-22 22:40:21]

lgtm

[dcheng, 2015-01-22 22:57:15]

The CQ bit was checked by dcheng@chromium.org

[commit-bot: I haz the power, 2015-01-22 22:59:00]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/873463004/1

[commit-bot: I haz the power, 2015-01-23 01:04:18]

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

[commit-bot: I haz the power, 2015-01-23 01:04:19]

Exceeded time limit waiting for builds to trigger.

[dcheng, 2015-01-23 01:05:32]

The CQ bit was checked by dcheng@chromium.org

[commit-bot: I haz the power, 2015-01-23 01:06:50]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/873463004/1

[commit-bot: I haz the power, 2015-01-23 03:09:43]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-01-23 03:10:42]

Patchset 1 (id:??) landed as
https://crrev.com/ee9fd750d987501be2d167ebe602333dfa19458c
Cr-Commit-Position: refs/heads/master@{#312745}