[Remote suggestions] Remove the unique_ptr wrapper around callbacks

components/ntp_snippets/remote/remote_suggestions_provider_impl.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_REMOTE_REMOTE_SUGGESTIONS_PROVIDER_IMPL_H_
 #define COMPONENTS_NTP_SNIPPETS_REMOTE_REMOTE_SUGGESTIONS_PROVIDER_IMPL_H_
 
 #include <cstddef>
 #include <deque>
 #include <map>
@@ skipping 119 matching lines @@
   // Returns whether the service is ready. While this is false, the list of
   // suggestions will be empty, and all modifications to it (fetch, dismiss,
   // etc) will be ignored.
   bool ready() const { return state_ == State::READY; }
 
   // Returns whether the service is successfully initialized. While this is
   // false, some calls may trigger DCHECKs.
   bool initialized() const { return ready() || state_ == State::DISABLED; }
 
   // RemoteSuggestionsProvider implementation.
-  void RefetchInTheBackground(
-      std::unique_ptr<FetchStatusCallback> callback) override;
+  void RefetchInTheBackground(const FetchStatusCallback& callback) override;
 
   // TODO(fhorschig): Remove this getter when there is an interface for the
   // fetcher that allows better mocks.
   const RemoteSuggestionsFetcher* suggestions_fetcher_for_debugging()
       const override;
 
   // ContentSuggestionsProvider implementation.
   CategoryStatus GetCategoryStatus(Category category) override;
   CategoryInfo GetCategoryInfo(Category category) override;
   void DismissSuggestion(const ContentSuggestion::ID& suggestion_id) override;
@@ skipping 134 matching lines @@
     CategoryContent& operator=(CategoryContent&&);
   };
 
   // Fetches suggestions from the server and replaces old suggestions by the new
   // ones. Requests can be marked more important by setting
   // |interactive_request| to true (such request might circumvent the daily
   // quota for requests, etc.), useful for requests triggered by the user. After
   // the fetch finished, the provided |callback| will be triggered with the
   // status of the fetch.
   void FetchSuggestions(bool interactive_request,
-                        std::unique_ptr<FetchStatusCallback> callback);
+                        const FetchStatusCallback& callback);
 
   // Returns the URL of the image of a suggestion if it is among the current or
   // among the archived suggestions in the matching category. Returns an empty
   // URL otherwise.
   GURL FindSuggestionImageUrl(const ContentSuggestion::ID& suggestion_id) const;
 
   // Callbacks for the RemoteSuggestionsDatabase.
   void OnDatabaseLoaded(RemoteSuggestion::PtrVector suggestions);
   void OnDatabaseError();
 
   // Callback for fetch-more requests with the RemoteSuggestionsFetcher.
   void OnFetchMoreFinished(
       const FetchDoneCallback& fetching_callback,
       Status status,
       RemoteSuggestionsFetcher::OptionalFetchedCategories fetched_categories);
 
   // Callback for regular fetch requests with the RemoteSuggestionsFetcher.
   void OnFetchFinished(
-      std::unique_ptr<FetchStatusCallback> callback,
+      const FetchStatusCallback& callback,
       bool interactive_request,
       Status status,
       RemoteSuggestionsFetcher::OptionalFetchedCategories fetched_categories);
 
   // Moves all suggestions from |to_archive| into the archive of the |content|.
   // Clears |to_archive|. As the archive is a FIFO buffer of limited size, this
   // function will also delete images from the database in case the associated
   // suggestion gets evicted from the archive.
   void ArchiveSuggestions(CategoryContent* content,
                           RemoteSuggestion::PtrVector* to_archive);
@@ skipping 115 matching lines @@
   // The service that provides events and data about the signin and sync state.
   std::unique_ptr<RemoteSuggestionsStatusService> status_service_;
 
   // Set to true if FetchSuggestions is called while the service isn't ready.
   // The fetch will be executed once the service enters the READY state.
   // TODO(jkrcal): create a struct and have here just one base::Optional<>?
   bool fetch_when_ready_;
 
   // The parameters for the fetch to perform later.
   bool fetch_when_ready_interactive_;
-  std::unique_ptr<FetchStatusCallback> fetch_when_ready_callback_;
+  FetchStatusCallback fetch_when_ready_callback_;
 
   // Set to true if ClearHistoryDependentState is called while the service isn't
   // ready. The nuke will be executed once the service finishes initialization
   // or enters the READY state.
   bool clear_history_dependent_state_when_initialized_;
 
   // A clock for getting the time. This allows to inject a clock in tests.
   std::unique_ptr<base::Clock> clock_;
 
   DISALLOW_COPY_AND_ASSIGN(RemoteSuggestionsProviderImpl);
 };
 
 }  // namespace ntp_snippets
 
 #endif  // COMPONENTS_NTP_SNIPPETS_REMOTE_REMOTE_SUGGESTIONS_PROVIDER_IMPL_H_