Don't try to access an Isolate when don't have one yet.

Don't try to access an Isolate when don't have one yet.

BUG=373385
R=jochen@chromium.org
NOTRY=true

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=270986

[jochen (gone - plz use gerrit), 2014-05-16 09:29:45]

lgtm

[Sven Panne, 2014-05-16 09:30:55]

The CQ bit was checked by svenpanne@chromium.org

[commit-bot: I haz the power, 2014-05-16 09:31:39]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/svenpanne@chromium.org/289033006/1

[commit-bot: I haz the power, 2014-05-16 11:06:09]

FYI, CQ is re-trying this CL (attempt #1).
Please consider checking whether the failures are real,
and report flakes to chrome-troopers@google.com.
The failing builders are:
  android_dbg_triggered_tests on tryserver.chromium
(http://build.chromium.org/p/tryserver.chromium/builders/android_dbg_triggered...)
  ios_rel_device_ninja on tryserver.chromium
(http://build.chromium.org/p/tryserver.chromium/builders/ios_rel_device_ninja/...)

[commit-bot: I haz the power, 2014-05-16 11:08:09]

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

[commit-bot: I haz the power, 2014-05-16 11:08:09]

Try jobs failed on following builders:
  ios_rel_device_ninja on tryserver.chromium
(http://build.chromium.org/p/tryserver.chromium/builders/ios_rel_device_ninja/...)

[Michael Achenbach, 2014-05-16 11:17:10]

The CQ bit was checked by machenbach@chromium.org

[commit-bot: I haz the power, 2014-05-16 11:17:31]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/svenpanne@chromium.org/289033006/1

[commit-bot: I haz the power, 2014-05-16 11:18:19]

Change committed as 270986

[Michael Achenbach, 2014-05-16 11:22:20]

In cases this gets reverted and also https://codereview.chromium.org/288193003/
lands in the mean time, it might cause the telemetry perf unittest to fail
again. See issue 373385.