[PushMessaging] Use appopriate type parameters for WebCallbacks (2/3).

[PushMessaging] Use appopriate type parameters for WebCallbacks (2/3).

This series of CLs fixes WebCallback parameter types used in PushMessaging.

 - WebPushSubscription* (ownership transferred)
  => PassOwnPtr<WebPushSubscription>
 - WebPushPermissionStatus* (ownership not transferred)
  => WebPushPermissionStatus
 - WebPushError* (ownership transferred)
  => const WebPushError&

1/3: https://codereview.chromium.org/1304723002/
2/3: https://codereview.chromium.org/1291023005/
3/3: https://codereview.chromium.org/1302833004/

BUG=493531
Committed: https://crrev.com/ff15b742ada731603ef9070b8fa3f18ed1b45111
Cr-Commit-Position: refs/heads/master@{#344673}

[yhirano, 2015-08-20 06:19:34]

yhirano@chromium.org changed reviewers:
+ peter@chromium.org

[Michael van Ouwerkerk, 2015-08-20 13:32:23]

mvanouwerkerk@chromium.org changed reviewers:
+ mvanouwerkerk@chromium.org

[Michael van Ouwerkerk, 2015-08-20 13:32:23]

lgtm

[yhirano, 2015-08-21 01:05:39]

The CQ bit was checked by yhirano@chromium.org

[commit-bot: I haz the power, 2015-08-21 01:08:04]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1291023005/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1291023005/20001

[commit-bot: I haz the power, 2015-08-21 03:17:15]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-08-21 03:17:56]

Patchset 2 (id:??) landed as
https://crrev.com/ff15b742ada731603ef9070b8fa3f18ed1b45111
Cr-Commit-Position: refs/heads/master@{#344673}