[ios] Reduces height of DiscoverFeed header

Comparison image:
https://drive.google.com/file/d/1YqxC7U2VQ_X318GDHVmu6tOJnEblOQFs/view?usp=sharing
(Left:New Right:Old)

Bug: 1085419
Change-Id: I0ba685cf36db42e41daf11d7735600cffb5408a7
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2355310
Commit-Queue: Sergio Collazos <sczs@chromium.org>
Auto-Submit: Sergio Collazos <sczs@chromium.org>
Reviewed-by: Ganggui Tang <gogerald@chromium.org>
Cr-Commit-Position: refs/heads/master@{#798207}

ios/chrome/browser/ui/content_suggestions/cells/content_suggestions_discover_header_item.mm

@@ -27,7 +27,7 @@ const CGFloat kHeaderBorderMargin = 16;
 // Font size for label text in header.
 const CGFloat kDiscoverFeedTitleFontSize = 16;
 // Insets for header menu button.
-const CGFloat kHeaderMenuButtonInsetTopAndBottom = 11;
+const CGFloat kHeaderMenuButtonInsetTopAndBottom = 2;
 const CGFloat kHeaderMenuButtonInsetSides = 2;
 // Duration for the header animation when Discover feed visibility changes.
 const CGFloat kHeaderChangeAnimationDuration = 0.5;

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

@@ -53,6 +53,8 @@ const CGFloat kCardBorderRadius = 11;
 const CGFloat kDiscoverFeedContentWith = 430;
 // Value representing offset from bottom of the page to trigger pagination.
 const CGFloat kPaginationOffset = 100;
+// Height for the Discover Feed section header.
+const CGFloat kDiscoverFeedFeaderHeight = 30;
 }
 
 NSString* const kContentSuggestionsMostVisitedAccessibilityIdentifierPrefix =
@@ -605,6 +607,9 @@ NSString* const kContentSuggestionsMostVisitedAccessibilityIdentifierPrefix =
   if ([self.collectionUpdater isHeaderSection:section]) {
     return CGSizeMake(0, [self.headerSynchronizer headerHeight]);
   }
+  if ([self.collectionUpdater isDiscoverSection:section]) {
+    return CGSizeMake(0, kDiscoverFeedFeaderHeight);
+  }
   CGSize defaultSize = [super collectionView:collectionView
                                       layout:collectionViewLayout
              referenceSizeForHeaderInSection:section];