[Remote suggestions] Move the throttler into the Scheduler

components/ntp_snippets/remote/scheduling_remote_suggestions_provider.h

Index: components/ntp_snippets/remote/scheduling_remote_suggestions_provider.h
diff --git a/components/ntp_snippets/remote/scheduling_remote_suggestions_provider.h b/components/ntp_snippets/remote/scheduling_remote_suggestions_provider.h
index 5d6981220317f19ead2e6539a16342631376f525..35946a15229d5400bf0026bc03810e7d33574597 100644
--- a/components/ntp_snippets/remote/scheduling_remote_suggestions_provider.h
+++ b/components/ntp_snippets/remote/scheduling_remote_suggestions_provider.h
@@ -17,6 +17,7 @@
 #include "components/ntp_snippets/remote/persistent_scheduler.h"
 #include "components/ntp_snippets/remote/remote_suggestions_provider.h"
 #include "components/ntp_snippets/remote/remote_suggestions_scheduler.h"
+#include "components/ntp_snippets/remote/request_throttler.h"
 
 class PrefRegistrySimple;
 class PrefService;
@@ -146,6 +147,9 @@ class SchedulingRemoteSuggestionsProvider final
   // Returns whether background fetching (for the given |trigger|) is disabled.
   bool BackgroundFetchesDisabled(TriggerType trigger) const;
 
+  // Returns true if quota is available for another request.
+  bool DemandQuotaForRequest(bool interactive_request);

[tschumann, 2017/02/24 10:18:08]

nit: would AcquireQuota() be a better name? We have much better context here, so
we can afford shorter names.

[jkrcal, 2017/02/27 10:26:23]

Done.

+
   // Callback after Fetch is completed.
   void FetchFinished(const FetchDoneCallback& callback,
                      Status fetch_status,
@@ -191,6 +195,11 @@ class SchedulingRemoteSuggestionsProvider final
   // Used to adapt the schedule based on usage activity of the user. Not owned.
   const UserClassifier* user_classifier_;
 
+  // Request throttlers for limiting requests for different classes of users.
+  RequestThrottler request_throttler_rare_ntp_user_;
+  RequestThrottler request_throttler_active_ntp_user_;
+  RequestThrottler request_throttler_active_suggestions_consumer_;
+
   PrefService* pref_service_;
   std::unique_ptr<base::Clock> clock_;
   std::set<SchedulingRemoteSuggestionsProvider::TriggerType> enabled_triggers_;