Fix some override usage in media/

Fix some override usage in media/

Currently, the Clang style checker ignores templates. In order to turn it on,
we first must fix latent style violations. This CL covers media/

BUG=441916
R=dalecurtis@chromium.org

Committed: https://crrev.com/5c2a4caa4e3eb8352167a647c48bb7ef0d78d00d
Cr-Commit-Position: refs/heads/master@{#309268}

[dmichael (off chromium), 2014-12-19 19:50:17]

The CQ bit was checked by dmichael@chromium.org

[commit-bot: I haz the power, 2014-12-19 19:51:40]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/820733002/1

[commit-bot: I haz the power, 2014-12-19 19:51:41]

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

[commit-bot: I haz the power, 2014-12-19 19:51:42]

No LGTM from a valid reviewer yet. Only full committers are accepted.
Even if an LGTM may have been provided, it was from a non-committer,
_not_ a full super star committer.
See http://www.chromium.org/getting-involved/become-a-committer
Note that this has nothing to do with OWNERS files.

[scherkus (not reviewing), 2014-12-19 19:52:03]

scherkus@chromium.org changed reviewers:
+ scherkus@chromium.org

[scherkus (not reviewing), 2014-12-19 19:52:04]

lgtm (he's OOO)

[dmichael (off chromium), 2014-12-19 19:59:50]

On 2014/12/19 19:52:04, scherkus wrote:
> lgtm (he's OOO)
Oops, meant to TBR since it's trivial style cleanup. Thanks for looking!

[dmichael (off chromium), 2014-12-19 19:59:52]

The CQ bit was checked by dmichael@chromium.org

[commit-bot: I haz the power, 2014-12-19 20:00:48]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/820733002/1

[commit-bot: I haz the power, 2014-12-19 21:39:11]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2014-12-19 21:39:57]

Patchset 1 (id:??) landed as
https://crrev.com/5c2a4caa4e3eb8352167a647c48bb7ef0d78d00d
Cr-Commit-Position: refs/heads/master@{#309268}