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

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

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
Committed: https://crrev.com/8e3e03ecaadd10689ee34e65dce9d39cef123d65
Cr-Commit-Position: refs/heads/master@{#314951}

[dcheng, 2015-02-06 01:02:15]

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

[Lei Zhang, 2015-02-06 01:13:39]

lgtm

[dcheng, 2015-02-06 01:14:13]

The CQ bit was checked by dcheng@chromium.org

[commit-bot: I haz the power, 2015-02-06 01:14:46]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/900613004/1

[commit-bot: I haz the power, 2015-02-06 03:32:50]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-02-06 03:33:56]

Patchset 1 (id:??) landed as
https://crrev.com/8e3e03ecaadd10689ee34e65dce9d39cef123d65
Cr-Commit-Position: refs/heads/master@{#314951}