Update {virtual,override,final} to follow C++11 style in chromeos.

Update {virtual,override,final} to follow C++11 style in 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=zelidrag@chromium.org

Committed: https://crrev.com/ae98daac90e8a97f807911858856fcb402c36860
Cr-Commit-Position: refs/heads/master@{#312426}

[dcheng, 2015-01-20 18:25:15]

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

[dcheng, 2015-01-20 18:25:16]

+oshima

[dcheng, 2015-01-21 19:05:10]

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

[dcheng, 2015-01-21 19:05:10]

+derat, any chance you can take a look at this? This is the last large patch
blocking the CrOS flag changes for the plugin.

[Daniel Erat, 2015-01-21 19:30:33]

sure! lgtm

[dcheng, 2015-01-21 19:43:07]

The CQ bit was checked by dcheng@chromium.org

[commit-bot: I haz the power, 2015-01-21 19:44:26]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/856563004/1

[commit-bot: I haz the power, 2015-01-21 20:31:16]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-01-21 20:32:27]

Patchset 1 (id:??) landed as
https://crrev.com/ae98daac90e8a97f807911858856fcb402c36860
Cr-Commit-Position: refs/heads/master@{#312426}