Inform server of dismissed articles.

components/ntp_snippets/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_NTP_SNIPPETS_FETCHER_H_
 #define COMPONENTS_NTP_SNIPPETS_NTP_SNIPPETS_FETCHER_H_
 
 #include <memory>
 #include <set>
 #include <string>
@@ skipping 72 matching lines @@
       CategoryFactory* category_factory,
       const ParseJSONCallback& parse_json_callback,
       bool is_stable_channel);
   ~NTPSnippetsFetcher() override;
 
   // Set a callback that is called when a new set of snippets are downloaded,
   // overriding any previously set callback.
   void SetCallback(const SnippetsAvailableCallback& callback);
 
   // Fetches snippets from the server. |hosts| restricts the results to a set of
-  // hosts, e.g. "www.google.com". An empty host set produces an error.
+  // hosts, e.g. "www.google.com". If host restrictions are enabled, an empty
+  // host set produces an error without issuing a fetch.
+  //
+  // |excluded_ids| will be reported to the server; the server should not return
+  // suggestions with those IDs.
   //
   // If an ongoing fetch exists, it will be cancelled and a new one started,
   // without triggering an additional callback (i.e. not noticeable by
   // subscriber of SetCallback()).
   //
   // Fetches snippets only if the daily quota not exceeded, unless
   // |interactive_request| is set to true (use only for user-initiated fetches).
   void FetchSnippetsFromHosts(const std::set<std::string>& hosts,
                               const std::string& language_code,
+                              const std::set<std::string>& excluded_ids,
                               int count,
                               bool interactive_request);
 
   // Debug string representing the status/result of the last fetch attempt.
   const std::string& last_status() const { return last_status_; }
 
   // Returns the last JSON fetched from the server.
   const std::string& last_json() const {
     return last_fetch_json_;
   }
@@ skipping 14 matching lines @@
     tick_clock_ = std::move(tick_clock);
   }
 
   void SetPersonalizationForTesting(Personalization personalization) {
     personalization_ = personalization;
   }
 
  private:
   FRIEND_TEST_ALL_PREFIXES(NTPSnippetsFetcherTest, BuildRequestAuthenticated);
   FRIEND_TEST_ALL_PREFIXES(NTPSnippetsFetcherTest, BuildRequestUnauthenticated);
+  FRIEND_TEST_ALL_PREFIXES(NTPSnippetsFetcherTest, BuildRequestExcludedIds);
 
   enum FetchAPI {
     CHROME_READER_API,
     CHROME_CONTENT_SUGGESTIONS_API,
   };
 
   struct RequestParams {
     FetchAPI fetch_api;
     std::string obfuscated_gaia_id;
     bool only_return_personalized_results;
     std::string user_locale;
     std::set<std::string> host_restricts;
+    std::set<std::string> excluded_ids;
     int count_to_fetch;
 
     RequestParams();
     ~RequestParams();
 
     std::string BuildRequest();
   };
 
   void FetchSnippetsImpl(const GURL& url,
                          const std::string& auth_header,
@@ skipping 35 matching lines @@
 
   CategoryFactory* const category_factory_;
   const ParseJSONCallback parse_json_callback_;
   base::TimeTicks fetch_start_time_;
   std::string last_status_;
   std::string last_fetch_json_;
 
   // Hosts to restrict the snippets to.
   std::set<std::string> hosts_;
 
+  // Snippets to exclude from the results.
+  std::set<std::string> excluded_ids_;
+
   // Count of snippets to fetch.
   int count_to_fetch_;
 
   // Language code to restrict to for personalized results.
   std::string locale_;
 
   // API endpoint for fetching snippets.
   const GURL fetch_url_;
   // Which API to use
   const FetchAPI fetch_api_;
@@ skipping 21 matching lines @@
   // When a token request gets canceled, we want to retry once.
   bool oauth_token_retried_;
 
   base::WeakPtrFactory<NTPSnippetsFetcher> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(NTPSnippetsFetcher);
 };
 }  // namespace ntp_snippets
 
 #endif  // COMPONENTS_NTP_SNIPPETS_NTP_SNIPPETS_FETCHER_H_