RemoteContentSuggestions: Stores the time of the last successful background fetch in a pref

components/ntp_snippets/remote/ntp_snippets_fetcher.h

 // Copyright 2016 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_NTP_SNIPPETS_FETCHER_H_
 #define COMPONENTS_NTP_SNIPPETS_REMOTE_NTP_SNIPPETS_FETCHER_H_
 
 #include <memory>
 #include <queue>
 #include <set>
@@ skipping 62 matching lines @@
     NTPSnippet::PtrVector snippets;
 
     FetchedCategory(Category c, CategoryInfo&& info);
     FetchedCategory(FetchedCategory&&);             // = default, in .cc
     ~FetchedCategory();                             // = default, in .cc
     FetchedCategory& operator=(FetchedCategory&&);  // = default, in .cc
   };
   using FetchedCategoriesVector = std::vector<FetchedCategory>;
   using OptionalFetchedCategories = base::Optional<FetchedCategoriesVector>;
 
-  // |snippets| contains parsed snippets if a fetch succeeded. If problems
-  // occur, |snippets| contains no value (no actual vector in base::Optional).
-  // Error details can be retrieved using last_status().
-  using SnippetsAvailableCallback =
-      base::OnceCallback<void(OptionalFetchedCategories fetched_categories)>;
-
   // Enumeration listing all possible outcomes for fetch attempts. Used for UMA
   // histograms, so do not change existing values. Insert new values at the end,
   // and update the histogram definition.
   enum class FetchResult {
     SUCCESS,
     DEPRECATED_EMPTY_HOSTS,
     URL_REQUEST_STATUS_ERROR,
     HTTP_ERROR,
     JSON_PARSE_ERROR,
     INVALID_SNIPPET_CONTENT_ERROR,
     OAUTH_TOKEN_ERROR,
     INTERACTIVE_QUOTA_ERROR,
     NON_INTERACTIVE_QUOTA_ERROR,
     RESULT_MAX
   };
 
+  // |snippets| contains parsed snippets if a fetch succeeded. If problems
+  // occur, |snippets| contains no value (no actual vector in base::Optional).
+  // Error details can be retrieved using last_status().
+  using SnippetsAvailableCallback =
+      base::OnceCallback<void(FetchResult fetch_result,
+                              OptionalFetchedCategories fetched_categories)>;
+
   // Enumeration listing all possible variants of dealing with personalization.
   enum class Personalization { kPersonal, kNonPersonal, kBoth };
 
   // Contains all the parameters for one fetch.
   struct Params {
     Params();
     Params(const Params&);
     ~Params();
 
     // If non-empty, restricts the result to the given set of hosts.
@@ skipping 242 matching lines @@
   std::string last_status_;
   std::string last_fetch_json_;
 
   base::WeakPtrFactory<NTPSnippetsFetcher> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(NTPSnippetsFetcher);
 };
 }  // namespace ntp_snippets
 
 #endif  // COMPONENTS_NTP_SNIPPETS_REMOTE_NTP_SNIPPETS_FETCHER_H_