[NTP::SectionOrder] Make ClickBasedRanker move dismissed sections down.

components/ntp_snippets/content_suggestions_service.cc

 // 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.
 
 #include "components/ntp_snippets/content_suggestions_service.h"
 
 #include <algorithm>
 #include <iterator>
 #include <set>
 #include <utility>
@@ skipping 179 matching lines @@
   auto providers_it = providers_by_category_.find(category);
   if (providers_it == providers_by_category_.end()) {
     return;
   }
 
   ContentSuggestionsProvider* provider = providers_it->second;
   UnregisterCategory(category, provider);
 
   dismissed_providers_by_category_[category] = provider;
   StoreDismissedCategoriesToPrefs();
+
+  category_ranker_->OnCategoryDismissed(category);
 }
 
 void ContentSuggestionsService::RestoreDismissedCategories() {
   // Make a copy as the original will be modified during iteration.
   auto dismissed_providers_by_category_copy = dismissed_providers_by_category_;
   for (const auto& category_provider_pair :
        dismissed_providers_by_category_copy) {
     RestoreDismissedCategory(category_provider_pair.first);
   }
   StoreDismissedCategoriesToPrefs();
@@ skipping 294 matching lines @@
 void ContentSuggestionsService::StoreDismissedCategoriesToPrefs() {
   base::ListValue list;
   for (const auto& category_provider_pair : dismissed_providers_by_category_) {
     list.AppendInteger(category_provider_pair.first.id());
   }
 
   pref_service_->Set(prefs::kDismissedCategories, list);
 }
 
 }  // namespace ntp_snippets