Standardize usage of virtual/override/final in gpu/

Standardize usage of virtual/override/final in gpu/

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

The generator for the GLES2 command buffers has also been updated.

BUG=417463
TBR=piman@chromium.org

Committed: https://crrev.com/1f4d1d7fb990754e14b53dd67dccdeb6b98ef719
Cr-Commit-Position: refs/heads/master@{#300496}

[dcheng, 2014-10-21 10:55:51]

The CQ bit was checked by dcheng@chromium.org

[commit-bot: I haz the power, 2014-10-21 10:57:27]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/663363002/20001

[commit-bot: I haz the power, 2014-10-21 12:56:50]

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

[commit-bot: I haz the power, 2014-10-21 12:56:52]

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 15:43:45]

The CQ bit was checked by dcheng@chromium.org

[commit-bot: I haz the power, 2014-10-21 15:44:19]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/663363002/20001

[commit-bot: I haz the power, 2014-10-21 16:22:15]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2014-10-21 16:22:50]

Patchset 2 (id:??) landed as
https://crrev.com/1f4d1d7fb990754e14b53dd67dccdeb6b98ef719
Cr-Commit-Position: refs/heads/master@{#300496}