Standardize usage of virtual/override/final in sync/

Standardize usage of virtual/override/final in sync/

This patch was automatically generated by applying clang fixit hints
generated by the plugin to the source tree.

BUG=417463
TBR=maniscalco@chromium.org

Committed: https://crrev.com/393acf28e5f1fd88de91c916c36d83d844021b0a
Cr-Commit-Position: refs/heads/master@{#300499}

[dcheng, 2014-10-21 09:35:13]

The CQ bit was checked by dcheng@chromium.org

[commit-bot: I haz the power, 2014-10-21 09:36:54]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/642023004/1

[commit-bot: I haz the power, 2014-10-21 10:52:07]

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

[commit-bot: I haz the power, 2014-10-21 10:52:08]

Try jobs failed on following builders:
  linux_chromium_rel_swarming on tryserver.chromium.linux
(http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)

[dcheng, 2014-10-21 11:46:28]

The CQ bit was checked by dcheng@chromium.org

[commit-bot: I haz the power, 2014-10-21 11:49:02]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/642023004/1

[commit-bot: I haz the power, 2014-10-21 13:20:57]

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

[commit-bot: I haz the power, 2014-10-21 13:20:59]

Try jobs failed on following builders:
  linux_chromium_rel_swarming on tryserver.chromium.linux
(http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)

[dcheng, 2014-10-21 15:43:42]

The CQ bit was checked by dcheng@chromium.org

[commit-bot: I haz the power, 2014-10-21 15:44:17]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/642023004/1

[commit-bot: I haz the power, 2014-10-21 16:45:17]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2014-10-21 16:46:14]

Patchset 1 (id:??) landed as
https://crrev.com/393acf28e5f1fd88de91c916c36d83d844021b0a
Cr-Commit-Position: refs/heads/master@{#300499}