[Remote suggestions] Move all decisions to fetch to the scheduler

components/ntp_snippets/remote/remote_suggestions_provider.h

Index: components/ntp_snippets/remote/remote_suggestions_provider.h
diff --git a/components/ntp_snippets/remote/remote_suggestions_provider.h b/components/ntp_snippets/remote/remote_suggestions_provider.h
index c9f58c45fb10639a62bdddc4a7131906f75552a7..e94d5e6fc26abfb4990bc7c17767e1e35d9130cb 100644
--- a/components/ntp_snippets/remote/remote_suggestions_provider.h
+++ b/components/ntp_snippets/remote/remote_suggestions_provider.h
@@ -14,19 +14,12 @@
 namespace ntp_snippets {
 
 class RemoteSuggestionsFetcher;
+class RemoteSuggestionsScheduler;
 
 // Retrieves fresh content data (articles) from the server, stores them and
 // provides them as content suggestions.
 class RemoteSuggestionsProvider : public ContentSuggestionsProvider {
  public:
-  // TODO(jkrcal): Would be nice to get rid of this another level of statuses.
-  // Maybe possible while refactoring the RemoteSuggestionsStatusService? (and
-  // letting it notify both the SchedulingRemoteSuggestionsProvider and
-  // RemoteSuggestionsProviderImpl or just the scheduling one).
-  enum class ProviderStatus { ACTIVE, INACTIVE };
-  using ProviderStatusCallback =
-      base::RepeatingCallback<void(ProviderStatus status)>;
-
   // Callback to notify with the result of a fetch.
   // TODO(jkrcal): Change to OnceCallback? A OnceCallback does only have a
   // move-constructor which seems problematic for google mock.
@@ -34,13 +27,12 @@ class RemoteSuggestionsProvider : public ContentSuggestionsProvider {
 
   ~RemoteSuggestionsProvider() override;
 
-  // Set a callback to be notified whenever the status of the provider changes.
-  // The initial change is also notified (switching from an initial undecided
-  // status). If the callback is set after the first change, it is called back
-  // immediately.
-  // TODO(treib): Get rid of unique_ptrs to callbacks.
-  virtual void SetProviderStatusCallback(
-      std::unique_ptr<ProviderStatusCallback> callback) = 0;
+  // Set the scheduler to be notified whenever the provider becomes active /
+  // in-active and whenever history is deleted. The initial change is also
+  // notified (switching from an initial undecided status). If the scheduler is
+  // set after the first change, it is called back immediately.
+  virtual void SetRemoteSuggestionsScheduler(
+      RemoteSuggestionsScheduler* scheduler) = 0;
 
   // Fetches suggestions from the server for all remote categories and replaces
   // old suggestions by the new ones. The request to the server is performed as