Add ContentSuggestionsService

components/ntp_snippets/ntp_snippets_service.h

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef COMPONENTS_NTP_SNIPPETS_NTP_SNIPPETS_SERVICE_H_
 #define COMPONENTS_NTP_SNIPPETS_NTP_SNIPPETS_SERVICE_H_
 
 #include <stddef.h>
 
 #include <memory>
 #include <set>
 #include <string>
 #include <vector>
 
+#include "base/callback_forward.h"
 #include "base/gtest_prod_util.h"
 #include "base/macros.h"
 #include "base/observer_list.h"
 #include "base/timer/timer.h"
 #include "components/image_fetcher/image_fetcher_delegate.h"
 #include "components/keyed_service/core/keyed_service.h"
 #include "components/ntp_snippets/ntp_snippet.h"
 #include "components/ntp_snippets/ntp_snippets_fetcher.h"
 #include "components/ntp_snippets/ntp_snippets_scheduler.h"
 #include "components/ntp_snippets/ntp_snippets_status_service.h"
@@ skipping 292 matching lines @@
   // If the service might be enabled, DisabledReason::NONE will be provided.
   virtual void NTPSnippetsServiceDisabledReasonChanged(DisabledReason) = 0;
 
  protected:
   virtual ~NTPSnippetsServiceObserver() {}
 };
 
 }  // namespace ntp_snippets
 
 #endif  // COMPONENTS_NTP_SNIPPETS_NTP_SNIPPETS_SERVICE_H_