[BackgroundSyncManager] Remove dead code

Remove unused parameter.

Committed: https://crrev.com/0a76becb3c8bc0dce4a6b05a1c3b7a1c42053d1d
Cr-Commit-Position: refs/heads/master@{#324141}

[jkarlin, 2015-04-07 19:02:48]

jkarlin@chromium.org changed reviewers:
+ jsbell@chromium.org

[jkarlin, 2015-04-07 19:03:00]

jsbell: Please review all. Thanks!

[jsbell, 2015-04-07 20:05:49]

lgtm

Are there plans for future callers to RemoveRegistrationFromMap() to use the
old_registration param, or can that be removed too? (it looks like there's
currently only the one caller, unless codesearch is lying to me)

[jkarlin, 2015-04-07 20:43:50]

Removed that too, PTAL!

[jsbell, 2015-04-07 20:59:31]

Still lgtm

[jkarlin, 2015-04-07 21:13:34]

The CQ bit was checked by jkarlin@chromium.org

[commit-bot: I haz the power, 2015-04-07 21:14:21]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1059183004/20001

[commit-bot: I haz the power, 2015-04-07 22:53:41]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-04-07 22:54:38]

Patchset 2 (id:??) landed as
https://crrev.com/0a76becb3c8bc0dce4a6b05a1c3b7a1c42053d1d
Cr-Commit-Position: refs/heads/master@{#324141}