Service Worker: Use auto / range-based loop for container objects.

Service Worker: Use auto / range-based loop for container objects.

- Simplify for-loop in service_worker_storage.cc using auto / range-based loop.
This CL is a follow-up on https://codereview.chromium.org/1146913004/#msg59.
- Rename a variable name of RegistrationList type to align it to the other
names in the file.

BUG=N/A

Committed: https://crrev.com/ae3e369d08af8d272c0c4f1659762a5e4c39711d
Cr-Commit-Position: refs/heads/master@{#335142}

[jungkees, 2015-06-18 14:56:32]

jungkee.song@samsung.com changed reviewers:
+ falken@chromium.org, kinuko@chromium.org, michaeln@chromium.org,
nhiroki@chromium.org

[jungkees, 2015-06-18 14:57:27]

PTAL

[kinuko, 2015-06-18 19:47:51]

lgtm

[lgombos, 2015-06-18 21:03:03]

The CQ bit was checked by l.gombos@samsung.com

[commit-bot: I haz the power, 2015-06-18 21:05:19]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1192143002/1

[commit-bot: I haz the power, 2015-06-18 22:12:39]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-06-18 22:13:42]

Patchset 1 (id:??) landed as
https://crrev.com/ae3e369d08af8d272c0c4f1659762a5e4c39711d
Cr-Commit-Position: refs/heads/master@{#335142}