Add a tolerance factor to the test.

Add a tolerance factor to the test.

BUG=321237
R=eae@chromium.org,dsinclair@chromium.org

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=192559

[eae, 2015-03-24 18:24:12]

Code change looks good but please revert formatting changes, makes it harder to
see what changed and trace the history of the test.

[dsinclair, 2015-03-24 18:24:53]

lgtm

[szager1, 2015-03-24 19:39:19]

On 2015/03/24 18:24:12, eae wrote:
> Code change looks good but please revert formatting changes, makes it harder
to
> see what changed and trace the history of the test.

Done.

[szager1, 2015-03-24 19:39:24]

The CQ bit was checked by szager@chromium.org

[szager1, 2015-03-24 19:39:24]

The patchset sent to the CQ was uploaded after l-g-t-m from
dsinclair@chromium.org
Link to the patchset: https://codereview.chromium.org/1038463002/#ps40001
(title: "more formatting")

[commit-bot: I haz the power, 2015-03-24 19:39:35]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1038463002/40001

[commit-bot: I haz the power, 2015-03-25 00:15:13]

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

[commit-bot: I haz the power, 2015-03-25 00:15:14]

Try jobs failed on following builders:
  linux_blink_rel on tryserver.blink (JOB_FAILED,
http://build.chromium.org/p/tryserver.blink/builders/linux_blink_rel/builds/5...)

[szager1, 2015-03-25 17:40:16]

The CQ bit was checked by szager@chromium.org

[commit-bot: I haz the power, 2015-03-25 17:40:35]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1038463002/40001

[commit-bot: I haz the power, 2015-03-25 17:46:37]

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

[commit-bot: I haz the power, 2015-03-25 17:46:38]

Try jobs failed on following builders:
  linux_blink_rel on tryserver.blink (JOB_FAILED,
http://build.chromium.org/p/tryserver.blink/builders/linux_blink_rel/builds/5...)

[szager1, 2015-03-25 19:58:45]

The CQ bit was checked by szager@chromium.org

[szager1, 2015-03-25 19:58:45]

The patchset sent to the CQ was uploaded after l-g-t-m from
dsinclair@chromium.org
Link to the patchset: https://codereview.chromium.org/1038463002/#ps60001
(title: "rebase")

[commit-bot: I haz the power, 2015-03-25 19:59:02]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1038463002/60001

[commit-bot: I haz the power, 2015-03-25 22:12:00]

Committed patchset #4 (id:60001) as
https://src.chromium.org/viewvc/blink?view=rev&revision=192559