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=michaelbai@chromium.org

Committed: https://crrev.com/9b4dd1aa9e96c92ec4503eefea2c9770001f95f0
Cr-Commit-Position: refs/heads/master@{#314487}

[michaelbai, 2015-02-04 01:22:06]

lgtm

[dcheng, 2015-02-04 01:48:14]

The CQ bit was checked by dcheng@chromium.org

[commit-bot: I haz the power, 2015-02-04 01:48:47]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/893343002/1

[commit-bot: I haz the power, 2015-02-04 01:52:49]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2015-02-04 01:52:50]

Try jobs failed on following builders:
  ios_dbg_simulator on tryserver.chromium.mac
(http://build.chromium.org/p/tryserver.chromium.mac/builders/ios_dbg_simulator...)
  ios_rel_device_ng on tryserver.chromium.mac
(http://build.chromium.org/p/tryserver.chromium.mac/builders/ios_rel_device_ng...)
  ios_rel_device_ninja_ng on tryserver.chromium.mac
(http://build.chromium.org/p/tryserver.chromium.mac/builders/ios_rel_device_ni...)
  mac_chromium_compile_dbg_ng on tryserver.chromium.mac
(http://build.chromium.org/p/tryserver.chromium.mac/builders/mac_chromium_comp...)
  mac_chromium_rel_ng on tryserver.chromium.mac
(http://build.chromium.org/p/tryserver.chromium.mac/builders/mac_chromium_rel_...)

[dcheng, 2015-02-04 02:18:59]

New patchsets have been uploaded after l-g-t-m from michaelbai@chromium.org

[dcheng, 2015-02-04 02:19:23]

The CQ bit was checked by dcheng@chromium.org

[commit-bot: I haz the power, 2015-02-04 02:20:38]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/893343002/20001

[commit-bot: I haz the power, 2015-02-04 02:57:26]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-02-04 02:58:46]

Patchset 2 (id:??) landed as
https://crrev.com/9b4dd1aa9e96c92ec4503eefea2c9770001f95f0
Cr-Commit-Position: refs/heads/master@{#314487}