[iOS] Change Discover feed header visbility in all tabs

Updates collection updater's feed visibility to change header when feed
visibility is changed from a different tab.

Bug: 1126890, 1085419
Change-Id: I7bf3c3e7069c92940cade77973a050293451827c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2405624
Commit-Queue: Adam Trudeau-Arcaro <adamta@google.com>
Reviewed-by: Sergio Collazos <sczs@chromium.org>
Cr-Commit-Position: refs/heads/master@{#806207}

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

@@ -8,8 +8,13 @@
 // Consumer protocol for the content suggestions view controller.
 @protocol ContentSuggestionsConsumer
 // Notifies the consumer to set the content suggestions enabled
-// based on the user setting.
+// based on the user setting. Setting the feed to disabled removes the section
+// entirely, including the feed header.
 - (void)setContentSuggestionsEnabled:(BOOL)enabled;
+// Notifies the consumer to set the content suggestions visibility
+// based on the user setting. Setting the feed to invisible hides the feed
+// content, but retains the feed header.
+- (void)setContentSuggestionsVisible:(BOOL)visible;
 @end
 
 #endif  // IOS_CHROME_BROWSER_UI_CONTENT_SUGGESTIONS_CONTENT_SUGGESTIONS_CONSUMER_H_

ios/chrome/browser/ui/content_suggestions/content_suggestions_mediator.mm

@@ -618,6 +618,8 @@ const NSInteger kMaxNumMostVisitedTiles = 4;
   ContentSuggestionsSectionInformation* sectionInfo =
       self.sectionInformationByCategory[wrapper];
   sectionInfo.expanded = [self.contentArticlesExpanded value];
+  [self.consumer
+      setContentSuggestionsVisible:[self.contentArticlesExpanded value]];
 
   if (allData) {
     [self reloadAllData];

ios/chrome/browser/ui/content_suggestions/content_suggestions_view_controller.mm

@@ -808,6 +808,10 @@ NSString* const kContentSuggestionsMostVisitedAccessibilityIdentifierPrefix =
   _contentSuggestionsEnabled = enabled;
 }
 
+- (void)setContentSuggestionsVisible:(BOOL)visible {
+  [self.collectionUpdater changeDiscoverFeedHeaderVisibility:visible];
+}
+
 #pragma mark - NSKeyValueObserving
 
 // TODO(crbug.com/1114792): Remove once we stop containing the DiscoverFeed