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

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

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/e608bf1db146501034def593a8f5880d94d1c24a
Cr-Commit-Position: refs/heads/master@{#314998}

[dcheng, 2015-02-06 01:05:25]

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

[piman, 2015-02-06 03:38:31]

lgtm

[dcheng, 2015-02-06 06:37:16]

lgtm

[dcheng, 2015-02-06 06:37:23]

The CQ bit was checked by dcheng@chromium.org

[commit-bot: I haz the power, 2015-02-06 06:38:40]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/871293003/1

[commit-bot: I haz the power, 2015-02-06 07:33:15]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-02-06 07:34:39]

Patchset 1 (id:??) landed as
https://crrev.com/e608bf1db146501034def593a8f5880d94d1c24a
Cr-Commit-Position: refs/heads/master@{#314998}