provide static popular sites for first run

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 308 matching lines @@
     whitelist_tiles.push_back(std::move(tile));
   }
 
   return whitelist_tiles;
 }
 
 NTPTilesVector MostVisitedSites::CreatePopularSitesTiles(
     const NTPTilesVector& personal_tiles,
     const NTPTilesVector& whitelist_tiles) {
   // For child accounts popular sites tiles will not be added.
-  if (supervisor_ && supervisor_->IsChildProfile())
+  if ((supervisor_ && supervisor_->IsChildProfile()) ||
+      !ShouldShowPopularSites())

[sfiera, 2017/02/13 15:05:54]

I think this should be in the lower if-statement, after we've determined if we
would need to backfill with popular sites. Otherwise, calling
ShouldShowPopularSites() could put a user into a control or experiment group
when they won't actually see popular sites.

[fhorschig, 2017/02/13 18:13:44]

Okay.

     return NTPTilesVector();
 
   size_t num_tiles = personal_tiles.size() + whitelist_tiles.size();
   DCHECK_LE(num_tiles, static_cast<size_t>(num_sites_));
 
   // Collect non-blacklisted popular suggestions, skipping those already present
   // in the personal suggestions.
   size_t num_popular_sites_tiles = num_sites_ - num_tiles;
   NTPTilesVector popular_sites_tiles;
 
@@ skipping 70 matching lines @@
     return;
 
   observer_->OnMostVisitedURLsAvailable(current_tiles_);
 }
 
 void MostVisitedSites::OnPopularSitesDownloaded(bool success) {
   if (!success) {
     LOG(WARNING) << "Download of popular sites failed";
     return;
   }
-
-  // Re-build the tile list. Once done, this will notify the observer.
-  BuildCurrentTiles();
 }
 
 void MostVisitedSites::OnIconMadeAvailable(const GURL& site_url,
                                            bool newly_available) {
   if (newly_available)
     observer_->OnIconMadeAvailable(site_url);
 }
 
 void MostVisitedSites::TopSitesLoaded(TopSites* top_sites) {}
 
 void MostVisitedSites::TopSitesChanged(TopSites* top_sites,
                                        ChangeReason change_reason) {
   if (mv_source_ == NTPTileSource::TOP_SITES) {
     // The displayed tiles are invalidated.
     InitiateTopSitesQuery();
   }
 }
 
 }  // namespace ntp_tiles