Remove suggestions notified as invalid

ios/chrome/browser/content_suggestions/content_suggestions_coordinator.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_coordinator.h"
 
 #include "base/mac/scoped_nsobject.h"
 #include "base/strings/sys_string_conversions.h"
 #include "components/ntp_snippets/content_suggestions_service.h"
 #include "components/ntp_snippets/remote/remote_suggestions_scheduler.h"
@@ skipping 78 matching lines @@
                                         animated:YES
                                       completion:nil];
 }
 
 - (void)stop {
   [[self.navigationController presentingViewController]
       dismissViewControllerAnimated:YES
                          completion:nil];
   self.navigationController = nil;
   self.contentSuggestionsMediator = nil;
+  self.alertCoordinator = nil;
   _visible = NO;
 }
 
 #pragma mark - ContentSuggestionsCommands
 
 - (void)openReadingList {
 }
 
 - (void)openFirstPageOfReadingList {
 }
@@ skipping 60 matching lines @@
 
   [self.alertCoordinator addItemWithTitle:l10n_util::GetNSString(IDS_APP_CANCEL)
                                    action:^{
                                      // TODO(crbug.com/691979): Add metrics.
                                    }
                                     style:UIAlertActionStyleCancel];
 
   [self.alertCoordinator start];
 }
 
+- (void)dismissContextMenu {
+  [self.alertCoordinator stop];
+  self.alertCoordinator = nil;
+}
+
 #pragma mark - Private
 
 - (void)openNewTabWithURL:(const GURL&)URL incognito:(BOOL)incognito {
   // TODO(crbug.com/691979): Add metrics.
 
   [self.URLLoader webPageOrderedOpen:URL
                             referrer:web::Referrer()
                          inIncognito:incognito
                         inBackground:NO
                             appendTo:kLastTab];
 
   [self stop];
 }
 
 - (void)dismissArticle:(ContentSuggestionsArticleItem*)article
            atIndexPath:(NSIndexPath*)indexPath {
   if (!article)
     return;
 
   // TODO(crbug.com/691979): Add metrics.
   [self.contentSuggestionsMediator
       dismissSuggestion:article.suggestionIdentifier];
   [self.suggestionsViewController dismissEntryAtIndexPath:indexPath];
 }
 
 @end