DurableStorage: Fix compile failure on ChromeOS tryservers

DurableStorage: Fix compile failure on ChromeOS tryservers

Log samples:
http://build.chromium.org/p/tryserver.chromium.linux/builders/chromeos_x86-generic_chromium_compile_only_ng/builds/22022
http://build.chromium.org/p/tryserver.chromium.linux/builders/chromeos_daisy_chromium_compile_only_ng/builds/22118

This was added by:
https://codereview.chromium.org/1294913009

BUG=482814
Committed: https://crrev.com/c82958f19e0dfe384f40ed01c20974fd6189d4ce
Cr-Commit-Position: refs/heads/master@{#344431}

[nhiroki, 2015-08-20 04:30:50]

nhiroki@chromium.org changed reviewers:
+ dgrogan@chromium.org, kinuko@chromium.org

[nhiroki, 2015-08-20 04:32:53]

PTAL, thanks!

[kinuko, 2015-08-20 04:41:39]

lgtm

[nhiroki, 2015-08-20 04:42:06]

The CQ bit was checked by nhiroki@chromium.org

[commit-bot: I haz the power, 2015-08-20 04:42:12]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1301033004/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1301033004/1

[dgrogan, 2015-08-20 05:21:15]

lgtm

sorry and thanks

[commit-bot: I haz the power, 2015-08-20 05:47:23]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-08-20 05:48:04]

Patchset 1 (id:??) landed as
https://crrev.com/c82958f19e0dfe384f40ed01c20974fd6189d4ce
Cr-Commit-Position: refs/heads/master@{#344431}