[signin] Remove signin.allowed pref.
The signin.allowed policy has been deprecated. This CL removes both
the signin.allowed policy and the signin.allowed preference that was
used to back it up.
Bug: 870239
Change-Id: I91be7a30848ceffe31eabe3287b4672ae394a6ed
Reviewed-on: https://chromium-review.googlesource.com/1225800
Reviewed-by: Jochen Eisinger <jochen@chromium.org>
Reviewed-by: Ramin Halavati <rhalavati@chromium.org>
Reviewed-by: Julian Pastarmov <pastarmovj@chromium.org>
Reviewed-by: Marc Treib <treib@chromium.org>
Reviewed-by: Boris Sazonov <bsazonov@chromium.org>
Commit-Queue: Mihai Sardarescu <msarda@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#593117}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 485addda95acf5a4d791fd419a195e7480cd29ff4 files changed
