Introduce a helper that will be used by embedders of SigninClient to
delay callbacks when network is offline and fire them when online.

Both //ios/chrome and //ios/web_view needs to subclass SigninClient, and
this helper will be used to share code between them.

Bug: 774517
Change-Id: I1da0e5163ee65f0287483a022120ebc51045cd8b
Reviewed-on: https://chromium-review.googlesource.com/807328
Reviewed-by: Colin Blundell <blundell@chromium.org>
Reviewed-by: Mike Dougherty <michaeldo@chromium.org>
Reviewed-by: Mihai Sardarescu <msarda@chromium.org>
Commit-Queue: John Wu <jzw@chromium.org>
Cr-Commit-Position: refs/heads/master@{#522932}
6 files changed