Remove suggestions notified as invalid

ios/chrome/browser/content_suggestions/content_suggestions_coordinator.mm

Index: ios/chrome/browser/content_suggestions/content_suggestions_coordinator.mm
diff --git a/ios/chrome/browser/content_suggestions/content_suggestions_coordinator.mm b/ios/chrome/browser/content_suggestions/content_suggestions_coordinator.mm
index e0cf332a3e43234af723a7f7157e764fbed72d60..8aecdeaa494e5c2ee8ce7f64ba470b9bfa3e3d8b 100644
--- a/ios/chrome/browser/content_suggestions/content_suggestions_coordinator.mm
+++ b/ios/chrome/browser/content_suggestions/content_suggestions_coordinator.mm
@@ -96,6 +96,7 @@
                          completion:nil];
   self.navigationController = nil;
   self.contentSuggestionsMediator = nil;
+  self.alertCoordinator = nil;
   _visible = NO;
 }
 
@@ -176,6 +177,11 @@
   [self.alertCoordinator start];
 }
 
+- (void)dismissContextMenu {
+  [self.alertCoordinator stop];
+  self.alertCoordinator = nil;
+}
+
 #pragma mark - Private
 
 - (void)openNewTabWithURL:(const GURL&)URL incognito:(BOOL)incognito {