Add media_unittests to chromium_builder_webrtc GYP target.

Add media_unittests to chromium_builder_webrtc GYP target.

Also depend on chromium_builder_perf instead of chromium_builder_qa
since it's likely we'll start running Telemetry tests on our bots
in the near future.

BUG=

Committed: https://crrev.com/88f639b44ae2bb400ce3407c127ed57565662ef0
Cr-Commit-Position: refs/heads/master@{#295968}

[kjellander_chromium, 2014-09-22 09:05:05]

kjellander@chromium.org changed reviewers:
+ phoglund@chromium.org

[phoglund_chromium, 2014-09-22 13:08:04]

lgtm

[kjellander_chromium, 2014-09-22 13:10:45]

The CQ bit was checked by kjellander@chromium.org

[commit-bot: I haz the power, 2014-09-22 13:12:05]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/587173004/1

[commit-bot: I haz the power, 2014-09-22 14:32:59]

Committed patchset #1 (id:1) as d1376d8f06741710e0021f265632bef8864282ec

[commit-bot: I haz the power, 2014-09-22 14:33:33]

Patchset 1 (id:??) landed as
https://crrev.com/88f639b44ae2bb400ce3407c127ed57565662ef0
Cr-Commit-Position: refs/heads/master@{#295968}