FetchMore functionality backend

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 164 matching lines @@
 void ContentSuggestionsService::RemoveObserver(Observer* observer) {
   observers_.RemoveObserver(observer);
 }
 
 void ContentSuggestionsService::RegisterProvider(
     std::unique_ptr<ContentSuggestionsProvider> provider) {
   DCHECK(state_ == State::ENABLED);
   providers_.push_back(std::move(provider));
 }
 
+void ContentSuggestionsService::FetchMore(Category category) {
+  auto providers_it = providers_by_category_.find(category);
+  if (providers_it == providers_by_category_.end())
+    return;
+
+  providers_it->second->FetchMore();
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 // Private methods
 
 void ContentSuggestionsService::OnNewSuggestions(
     ContentSuggestionsProvider* provider,
     Category category,
     std::vector<ContentSuggestion> suggestions) {
   if (RegisterCategoryIfRequired(provider, category))
     NotifyCategoryStatusChanged(category);
 
@@ skipping 152 matching lines @@
           if (left.IsKnownCategory(KnownCategories::BOOKMARKS))
             return false;
           if (right.IsKnownCategory(KnownCategories::BOOKMARKS))
             return true;
         }
         return category_factory_.CompareCategories(left, right);
       });
 }
 
 }  // namespace ntp_snippets