Make OnPopularURLsAvailable optional.

components/ntp_tiles/most_visited_sites.cc

 // Copyright 2013 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.
 
 #include "components/ntp_tiles/most_visited_sites.h"
 
 #include <algorithm>
 #include <set>
 #include <string>
 #include <utility>
@@ skipping 122 matching lines @@
       return kHistogramWhitelistName;
     case NTPTileSource::SUGGESTIONS_SERVICE:
       return kHistogramServerName;
   }
   NOTREACHED();
   return std::string();
 }
 
 }  // namespace
 
+void MostVisitedSites::Observer::OnPopularURLsAvailable(
+    const PopularSitesVector& sites) {}

[Marc Treib, 2016/09/15 09:13:33]

Might as well put the empty body in the header. The dtor already does that.

[sfiera, 2016/09/21 08:35:26]

Done.

+
 MostVisitedSites::MostVisitedSites(PrefService* prefs,
                                    scoped_refptr<history::TopSites> top_sites,
                                    SuggestionsService* suggestions,
                                    std::unique_ptr<PopularSites> popular_sites,
                                    MostVisitedSitesSupervisor* supervisor)
     : prefs_(prefs),
       top_sites_(top_sites),
       suggestions_service_(suggestions),
       popular_sites_(std::move(popular_sites)),
       supervisor_(supervisor),
@@ skipping 391 matching lines @@
 
 void MostVisitedSites::TopSitesChanged(TopSites* top_sites,
                                        ChangeReason change_reason) {
   if (mv_source_ == NTPTileSource::TOP_SITES) {
     // The displayed tiles are invalidated.
     InitiateTopSitesQuery();
   }
 }
 
 }  // namespace ntp_tiles