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

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

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 an OS=android build using a
variation of https://codereview.chromium.org/598073004.

BUG=417463
R=aelias@chromium.org

Committed: https://crrev.com/c09395ec838d73d66ff900bb4d471ce931b192bd
Cr-Commit-Position: refs/heads/master@{#314477}

[aelias_OOO_until_Jul13, 2015-02-04 01:01:12]

lgtm

[dcheng, 2015-02-04 01:12:03]

The CQ bit was checked by dcheng@chromium.org

[commit-bot: I haz the power, 2015-02-04 01:12:50]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/897783002/1

[commit-bot: I haz the power, 2015-02-04 02:26:59]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-02-04 02:29:34]

Patchset 1 (id:??) landed as
https://crrev.com/c09395ec838d73d66ff900bb4d471ce931b192bd
Cr-Commit-Position: refs/heads/master@{#314477}