Update {virtual,override,final} to follow C++11 style in components, round 2.

Update {virtual,override,final} to follow C++11 style in components, round 2.

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
Committed: https://crrev.com/bd5bd4f4972ec164aa7811fb4bbc8fcc116168dd
Cr-Commit-Position: refs/heads/master@{#312855}

[dcheng, 2015-01-22 22:29:22]

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

[blundell, 2015-01-23 10:45:47]

lgtm

[dcheng, 2015-01-23 15:18:55]

The CQ bit was checked by dcheng@chromium.org

[commit-bot: I haz the power, 2015-01-23 15:20:00]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/865973003/20001

[commit-bot: I haz the power, 2015-01-23 16:02:16]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-01-23 16:03:30]

Patchset 2 (id:??) landed as
https://crrev.com/bd5bd4f4972ec164aa7811fb4bbc8fcc116168dd
Cr-Commit-Position: refs/heads/master@{#312855}