[Offline Pages] Add a GCMAppHandler for offline page prefetch.

components/offline_pages/core/prefetch/prefetch_service_impl.h

 // Copyright 2017 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_OFFLINE_PAGES_CORE_PREFETCH_PREFETCH_SERVICE_IMPL_H_
 #define COMPONENTS_OFFLINE_PAGES_CORE_PREFETCH_PREFETCH_SERVICE_IMPL_H_
 
-#include <vector>
+#include <memory>
 
 #include "components/offline_pages/core/prefetch/prefetch_service.h"
+#include "components/offline_pages/core/prefetch/suggested_articles_observer.h"
 #include "url/gurl.h"
 
+namespace ntp_snippets {
+class ContentSuggestionsService;
+}
+
 namespace offline_pages {
 
 class PrefetchServiceImpl : public PrefetchService {
  public:
-  PrefetchServiceImpl();
+  // An interface allowing the prefetch service to hold a GCM App Handler for
+  // lifetime purposes. TODO(dewittj): Add an interface method for getting an

[fgorski, 2017/05/17 23:15:02]

This comment is duplicated below, please remove one.

[dewittj, 2017/05/22 22:00:08]

Done.

+  // InstandID token.
+  class GCMAppHandler {
+   public:
+    virtual ~GCMAppHandler() = default;
+
+    // TODO(dewittj): Add methods for acquiring an Instance ID token to this
+    // interface.
+  };
+
+  explicit PrefetchServiceImpl(std::unique_ptr<GCMAppHandler> gcm_app_handler);
   ~PrefetchServiceImpl() override;
 
   // PrefetchService implementation:
+  void ObserveContentSuggestionsService(
+      ntp_snippets::ContentSuggestionsService* service) override;
   void AddCandidatePrefetchURLs(
       const std::vector<PrefetchURL>& suggested_urls) override;
   void RemoveAllUnprocessedPrefetchURLs(const std::string& name_space) override;
   void RemovePrefetchURLsByClientId(const ClientId& client_id) override;
   void BeginBackgroundTask(std::unique_ptr<ScopedBackgroundTask> task) override;
   void StopBackgroundTask(ScopedBackgroundTask* task) override;
 
   // KeyedService implementation:
   void Shutdown() override;
 
  private:
+  std::unique_ptr<SuggestedArticlesObserver> suggested_articles_observer_;
+  std::unique_ptr<GCMAppHandler> gcm_app_handler_;
+
   DISALLOW_COPY_AND_ASSIGN(PrefetchServiceImpl);
 };
 
 }  // namespace offline_pages
 
 #endif  // COMPONENTS_OFFLINE_PAGES_CORE_PREFETCH_PREFETCH_SERVICE_IMPL_H_