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

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

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 manually generated using a regex and a text editor.

BUG=417463
Committed: https://crrev.com/1b0cc2654f792b8865ca9615f247a881c23826b7
Cr-Commit-Position: refs/heads/master@{#326391}

[ncarter (slow), 2015-04-22 21:03:24]

nick@chromium.org changed reviewers:
+ jamescook@chromium.org

[James Cook, 2015-04-22 21:07:02]

lgtm

[ncarter (slow), 2015-04-22 21:14:59]

The CQ bit was checked by nick@chromium.org

[commit-bot: I haz the power, 2015-04-22 21:16:43]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1088593006/1

[commit-bot: I haz the power, 2015-04-22 23:15:17]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-04-22 23:16:02]

Patchset 1 (id:??) landed as
https://crrev.com/1b0cc2654f792b8865ca9615f247a881c23826b7
Cr-Commit-Position: refs/heads/master@{#326391}