Revert of Disable blink_perf.canvas on linux.

Revert of Disable blink_perf.canvas on linux. (patchset #1 id:1 of https://codereview.chromium.org/1129383007/)

Reason for revert:
Possible fix has landed, reverting to see if bot goes green.

Original issue's description:
> Disable blink_perf.canvas on linux.
>
> This has been red going on a week now.
>
> BUG=488059
> CQ_EXTRA_TRYBOTS=tryserver.chromium.perf:linux_perf_bisect;tryserver.chromium.perf:mac_perf_bisect;tryserver.chromium.perf:win_perf_bisect;tryserver.chromium.perf:android_nexus5_perf_bisect
>
> Committed: https://crrev.com/2e2d7141b8f141bfb194427afde9fb2bf1ed5486
> Cr-Commit-Position: refs/heads/master@{#330085}

TBR=sullivan@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=488059
Committed: https://crrev.com/c67128f7fb96c1e40bfb46a9ba7a1466a754f357
Cr-Commit-Position: refs/heads/master@{#330086}

[shatch, 2015-05-15 13:38:23]

Created Revert of Disable blink_perf.canvas on linux.

[commit-bot: I haz the power, 2015-05-15 13:38:37]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1142643002/1

[commit-bot: I haz the power, 2015-05-15 13:39:28]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-05-15 13:40:08]

Patchset 1 (id:??) landed as
https://crrev.com/c67128f7fb96c1e40bfb46a9ba7a1466a754f357
Cr-Commit-Position: refs/heads/master@{#330086}

[Sami, 2015-05-15 17:45:30]

A revert of this CL (patchset #1 id:1) has been created in
https://codereview.chromium.org/1131853007/ by skyostil@chromium.org.

The reason for reverting is: Looks like this is still failing consistently :(

http://build.chromium.org/p/chromium.perf/builders/Linux%20Perf%20(4).