[ServiceWorker] Re-enable service_worker.service_worker perf test.

[ServiceWorker] Re-enable service_worker.service_worker perf test.

This test was disabled because of the lack of avconv in the try bots.

BUG=433943
Committed: https://crrev.com/78e4cdcf2b533033c14e342e5d83440d3b5e749e
Cr-Commit-Position: refs/heads/master@{#307851}

[horo, 2014-12-11 01:30:25]

horo@chromium.org changed reviewers:
+ tonyg@chromium.org

[horo, 2014-12-11 01:30:25]

tonyg@
Could you please review this?

[tonyg, 2014-12-11 02:10:16]

lgtm

[horo, 2014-12-11 02:14:02]

The CQ bit was checked by horo@chromium.org

[commit-bot: I haz the power, 2014-12-11 02:15:48]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/794013002/1

[commit-bot: I haz the power, 2014-12-11 03:32:30]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2014-12-11 03:33:11]

Patchset 1 (id:??) landed as
https://crrev.com/78e4cdcf2b533033c14e342e5d83440d3b5e749e
Cr-Commit-Position: refs/heads/master@{#307851}

[oystein (OOO til 10th of July), 2015-02-03 04:25:58]

A revert of this CL (patchset #1 id:1) has been created in
https://codereview.chromium.org/883013005/ by oysteine@chromium.org.

The reason for reverting is: Still flaky on Mac.