Remove categories notified as invalid

ios/chrome/browser/ui/content_suggestions/content_suggestions_data_sink.h

 // Copyright 2017 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 IOS_CHROME_BROWSER_UI_CONTENT_SUGGESTIONS_CONTENT_SUGGESTIONS_DATA_SINK_H_
 #define IOS_CHROME_BROWSER_UI_CONTENT_SUGGESTIONS_CONTENT_SUGGESTIONS_DATA_SINK_H_
 
 @class ContentSuggestionIdentifier;
+@class ContentSuggestionsSectionInformation;
 
 // Data sink for the ContentSuggestions. It will be notified when new data needs
 // to be pulled.
 @protocol ContentSuggestionsDataSink
 
 // Notifies the Data Sink that new data is available.
 - (void)dataAvailable;
 
 // The suggestion associated with |suggestionIdentifier| has been invalidated by
 // the backend data source and should be cleared now. This is why this method is
 // about the data source pushing something to the data sink.
 - (void)clearSuggestion:(ContentSuggestionIdentifier*)suggestionIdentifier;
 
 // Notifies the Data Sink that it must remove all current data and reload new
 // ones.
 - (void)reloadAllData;
 
+// The section corresponding to |sectionInfo| has been invalidated and must be
+// cleared now. This is why this method is about the data source pushing
+// something to the data sink.
+- (void)clearSection:(ContentSuggestionsSectionInformation*)sectionInfo;
+
 @end
 
 #endif  // IOS_CHROME_BROWSER_UI_CONTENT_SUGGESTIONS_CONTENT_SUGGESTIONS_DATA_SINK_H_