[NTP Client] Put dismissing sections behind a flag

components/ntp_snippets/features.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_FEATURES_H_
 #define COMPONENTS_NTP_SNIPPETS_FEATURES_H_
 
 #include <string>
 
 #include "base/feature_list.h"
 
 namespace ntp_snippets {
 
 // Features to turn individual providers/categories on/off.
 extern const base::Feature kArticleSuggestionsFeature;
 extern const base::Feature kBookmarkSuggestionsFeature;
 extern const base::Feature kRecentOfflineTabSuggestionsFeature;
 extern const base::Feature kDownloadSuggestionsFeature;
 extern const base::Feature kPhysicalWebPageSuggestionsFeature;
-extern const base::Feature kForeignSessionsSuggestionsFeature;
+extern const base::Feature kForeignSessionsSuggestionsFeature;;
 
 // Feature to allow the 'save to offline' option to appear in the snippets
 // context menu.
 extern const base::Feature kSaveToOfflineFeature;
 
+// Feature to allow dismissing sections.
+extern const base::Feature kSectionDismissalFeature;
+
 // Global toggle for the whole content suggestions feature. If this is set to
 // false, all the per-provider features are ignored.
 extern const base::Feature kContentSuggestionsFeature;
 
 // Returns a feature param as an int instead of a string.
 int GetParamAsInt(const base::Feature& feature,
                   const std::string& param_name,
                   int default_value);
 
 }  // namespace ntp_snippets
 
 #endif  // COMPONENTS_NTP_SNIPPETS_FEATURES_H_