Add long press actions for Most Visited tiles

ios/chrome/browser/content_suggestions/content_suggestions_mediator.mm

 // 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.
 
 #import "ios/chrome/browser/content_suggestions/content_suggestions_mediator.h"
 
 #include "base/mac/bind_objc_block.h"
 #include "base/mac/foundation_util.h"
 #include "base/memory/ptr_util.h"
 #include "base/optional.h"
@@ skipping 107 matching lines @@
 - (void)dismissSuggestion:(ContentSuggestionIdentifier*)suggestionIdentifier {
   ContentSuggestionsCategoryWrapper* categoryWrapper =
       [self categoryWrapperForSectionInfo:suggestionIdentifier.sectionInfo];
   ntp_snippets::ContentSuggestion::ID suggestion_id =
       ntp_snippets::ContentSuggestion::ID([categoryWrapper category],
                                           suggestionIdentifier.IDInSection);
 
   self.contentService->DismissSuggestion(suggestion_id);
 }
 
+- (void)blacklistMostVisitedURL:(GURL)URL {
+  _mostVisitedSites->AddOrRemoveBlacklistedUrl(URL, true);
+}
+
+- (void)whitelistMostVisitedURL:(GURL)URL {
+  _mostVisitedSites->AddOrRemoveBlacklistedUrl(URL, false);
+}
+
 #pragma mark - ContentSuggestionsDataSource
 
 - (NSArray<ContentSuggestionsSectionInformation*>*)sectionsInfo {
   NSMutableArray<ContentSuggestionsSectionInformation*>* sectionsInfo =
       [NSMutableArray array];
 
   if (self.mostVisitedItems.count > 0) {
     [sectionsInfo addObject:self.mostVisitedSectionInfo];
   }
 
@@ skipping 312 matching lines @@
 }
 
 // Returns whether the |sectionInfo| is associated with a category from the
 // content suggestions service.
 - (BOOL)isRelatedToContentSuggestionsService:
     (ContentSuggestionsSectionInformation*)sectionInfo {
   return sectionInfo != self.mostVisitedSectionInfo;
 }
 
 @end