Update {virtual,override,final} to follow C++11 style chrome/browser/ui/webui/chromeos.

Update {virtual,override,final} to follow C++11 style chrome/browser/ui/webui/chromeos.

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
R=dbeam@chromium.org

Committed: https://crrev.com/4220eea6d0c7ffa94d59a996819af4b3f244829a
Cr-Commit-Position: refs/heads/master@{#312302}

[dcheng, 2015-01-20 18:24:57]

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

[dcheng, 2015-01-20 18:24:58]

+xiyuan

[xiyuan, 2015-01-20 22:40:45]

lgtm

[dcheng, 2015-01-20 22:41:12]

The CQ bit was checked by dcheng@chromium.org

[commit-bot: I haz the power, 2015-01-20 22:41:42]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/854063002/1

[commit-bot: I haz the power, 2015-01-21 00:21:04]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-01-21 00:21:52]

Patchset 1 (id:??) landed as
https://crrev.com/4220eea6d0c7ffa94d59a996819af4b3f244829a
Cr-Commit-Position: refs/heads/master@{#312302}