Revert "Revert of Implement getPermissionStatus in MockWebPushClient"

Revert "Revert of Implement getPermissionStatus in MockWebPushClient"

(patchset #3 id:40001 of https://codereview.chromium.org/677073002/)

This reverts commit 62bb47df51eac10a618b9ad5e4b15d2bae8ab6d6.

It was originally reverted because it broke one layout test in blink.
The problem with the layout test was in blink itself and fixed in
https://codereview.chromium.org/709733003/ so I am now relading this.

BUG=401424
TBR=tkent

Committed: https://crrev.com/7976e136c2a7a929e5e01f4d036455dc4b2f4c58
Cr-Commit-Position: refs/heads/master@{#303634}

[Miguel Garcia, 2014-11-11 12:11:34]

miguelg@chromium.org changed reviewers:
+ tkent@chromium.org

[Miguel Garcia, 2014-11-11 12:11:37]

The CQ bit was checked by miguelg@chromium.org

[commit-bot: I haz the power, 2014-11-11 12:12:40]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/716763002/1

[commit-bot: I haz the power, 2014-11-11 13:15:13]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2014-11-11 13:15:49]

Patchset 1 (id:??) landed as
https://crrev.com/7976e136c2a7a929e5e01f4d036455dc4b2f4c58
Cr-Commit-Position: refs/heads/master@{#303634}