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

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

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/9c7fbb29354afcaf0d2afbd1659128f7706f86fe
Cr-Commit-Position: refs/heads/master@{#326521}

[ncarter (slow), 2015-04-23 02:53:29]

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

[Roger Tawa OOO till Jul 10th, 2015-04-23 14:33:18]

lgtm

[ncarter (slow), 2015-04-23 14:45:34]

The CQ bit was checked by nick@chromium.org

[commit-bot: I haz the power, 2015-04-23 14:45:47]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1086453003/1

[commit-bot: I haz the power, 2015-04-23 15:12:09]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-04-23 15:12:57]

Patchset 1 (id:??) landed as
https://crrev.com/9c7fbb29354afcaf0d2afbd1659128f7706f86fe
Cr-Commit-Position: refs/heads/master@{#326521}