Have ServiceWorkerCache::Put return a Response when completed.

Have ServiceWorkerCache::Put return a Response when completed.

This gets Put() closer to the cache spec.

Downstream of: https://codereview.chromium.org/606843002/

BUG=392621
Committed: https://crrev.com/76de75164c1411d93b24d8e8be523c1d31bdd4bd
Cr-Commit-Position: refs/heads/master@{#297173}

[jkarlin, 2014-09-25 19:42:35]

jkarlin@chromium.org changed reviewers:
+ horo@chromium.org, michaeln@chromium.org

[jkarlin, 2014-09-25 19:42:35]

michaeln@chromium.org: Please review changes in everything

horo@chromium.org: Please review changes in everything

Thanks!

[horo, 2014-09-29 03:14:29]

lgtm

[jkarlin, 2014-09-29 13:24:27]

The CQ bit was checked by jkarlin@chromium.org

[commit-bot: I haz the power, 2014-09-29 13:24:37]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/608593003/20001

[commit-bot: I haz the power, 2014-09-29 14:37:40]

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

[commit-bot: I haz the power, 2014-09-29 14:37:41]

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

[jkarlin, 2014-09-29 15:01:53]

The CQ bit was checked by jkarlin@chromium.org

[commit-bot: I haz the power, 2014-09-29 15:02:35]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/608593003/20001

[commit-bot: I haz the power, 2014-09-29 15:03:22]

Committed patchset #2 (id:20001) as 47f33cd529acc0e73444de8e3c00d6a90c7df777

[commit-bot: I haz the power, 2014-09-29 15:04:27]

Patchset 2 (id:??) landed as
https://crrev.com/76de75164c1411d93b24d8e8be523c1d31bdd4bd
Cr-Commit-Position: refs/heads/master@{#297173}