Or another option: Get rid of the SchedulingRemoteSuggestionsProvider, and instead update RemoteSuggestionsProviderImpl to call the scheduler explicitly in all relevant cases.

(Pasting my comment from the CL:
IMO this whole design reaaally needs a re-think: The whole point of
introducing the SchedulingProvider wrapper was that the Impl wouldn't have to
know about the scheduling. If the Impl now knows about the Scheduler anyway,
then IMO we should be consistent, i.e. provide all scheduling events in that
way, and get rid of the wrapper.)

Also marking P1 in the hopes that this will actually get addressed :)

let's discuss this in person. I think we can adapt the current design slightly to get a nice separation. Looking at the amount of code in the scheduling wrapper, i'm actually quite happy we have a separate class.

It's not that the Impl shouldn't have to know about the existence of a scheduler -- it should just not care about the scheduling details.

Like I mentioned in the CL, it's possible that we're missing another interface that allows the scheduler to observe events of the IMPL. However, the providers already have a listener/observer concept and that might be confusing, too.

(notes to myself)

After refactoring of Scheduling... and Remote...Impl:
   * the main service owns them both as this needs to get revealed externally
   * they know about each other via the interfaces
   * RemoteImpl asks the scheduler before interactive fetches
   * Scheduling triggers the RemoteImpl on triggers
   * (there are corner-cases when snippets internals does the background fetch, we probably do not need to count it into quota)

As a next step, the status service could have power and control (similarly to the scheduler) what happens on sign-in / sign-out with no logic around that in Impl or Scheduler.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/f996646c9b3b4c8027e693c5a48c7fab3adbfe8c

commit f996646c9b3b4c8027e693c5a48c7fab3adbfe8c
Author: jkrcal <jkrcal@chromium.org>
Date: Wed Mar 29 16:25:21 2017

[Remote suggestions] Refactor the scheduler

This CL cleans up the relation of the scheduler and the provider of
remote suggestions. The previous wrapper pattern was not useful as there
was too much two-way communication between these two.

BUG= 695447 

Review-Url: https://codereview.chromium.org/2774663002
Cr-Commit-Position: refs/heads/master@{#460414}

[modify] https://crrev.com/f996646c9b3b4c8027e693c5a48c7fab3adbfe8c/chrome/browser/ntp_snippets/content_suggestions_service_factory.cc
[modify] https://crrev.com/f996646c9b3b4c8027e693c5a48c7fab3adbfe8c/chrome/browser/prefs/browser_prefs.cc
[modify] https://crrev.com/f996646c9b3b4c8027e693c5a48c7fab3adbfe8c/components/ntp_snippets/BUILD.gn
[modify] https://crrev.com/f996646c9b3b4c8027e693c5a48c7fab3adbfe8c/components/ntp_snippets/content_suggestions_service.cc
[modify] https://crrev.com/f996646c9b3b4c8027e693c5a48c7fab3adbfe8c/components/ntp_snippets/content_suggestions_service.h
[modify] https://crrev.com/f996646c9b3b4c8027e693c5a48c7fab3adbfe8c/components/ntp_snippets/content_suggestions_service_unittest.cc
[modify] https://crrev.com/f996646c9b3b4c8027e693c5a48c7fab3adbfe8c/components/ntp_snippets/remote/remote_suggestions_provider_impl.cc
[modify] https://crrev.com/f996646c9b3b4c8027e693c5a48c7fab3adbfe8c/components/ntp_snippets/remote/remote_suggestions_provider_impl.h
[modify] https://crrev.com/f996646c9b3b4c8027e693c5a48c7fab3adbfe8c/components/ntp_snippets/remote/remote_suggestions_provider_impl_unittest.cc
[modify] https://crrev.com/f996646c9b3b4c8027e693c5a48c7fab3adbfe8c/components/ntp_snippets/remote/remote_suggestions_scheduler.h
[rename] https://crrev.com/f996646c9b3b4c8027e693c5a48c7fab3adbfe8c/components/ntp_snippets/remote/remote_suggestions_scheduler_impl.cc
[add] https://crrev.com/f996646c9b3b4c8027e693c5a48c7fab3adbfe8c/components/ntp_snippets/remote/remote_suggestions_scheduler_impl.h
[rename] https://crrev.com/f996646c9b3b4c8027e693c5a48c7fab3adbfe8c/components/ntp_snippets/remote/remote_suggestions_scheduler_impl_unittest.cc
[delete] https://crrev.com/7a7a48cfbf8854d71104c5830403b1dab6830807/components/ntp_snippets/remote/scheduling_remote_suggestions_provider.h
[modify] https://crrev.com/f996646c9b3b4c8027e693c5a48c7fab3adbfe8c/ios/chrome/browser/ntp_snippets/ios_chrome_content_suggestions_service_factory.cc
[modify] https://crrev.com/f996646c9b3b4c8027e693c5a48c7fab3adbfe8c/ios/chrome/browser/prefs/browser_prefs.mm