Proper styling of the footer string.

Screenshot: http://imgur.com/a/7WXgf

BUG=602666

Review-Url: https://codereview.chromium.org/2807583003
Cr-Commit-Position: refs/heads/master@{#462951}

ios/chrome/browser/payments/payment_request_view_controller.mm

@@ -60,6 +60,8 @@ using ::payment_request_util::GetShippingOptionSelectorTitle;
 // as a link in the UI (see setLabelLinkURL: in CollectionViewFooterCell).
 const char kSettingsURL[] = "settings://card-and-address";
 
+const CGFloat kFooterCellHorizontalPadding = 16;
+
 }  // namespace
 
 NSString* const kPaymentRequestCollectionViewID =
@@ -519,6 +521,15 @@ typedef NS_ENUM(NSInteger, ItemType) {
           [[MDCPalette cr_bluePalette] tint700];
       break;
     }
+    case ItemTypeFooterText: {
+      CollectionViewFooterCell* footerCell =
+          base::mac::ObjCCastStrict<CollectionViewFooterCell>(cell);
+      footerCell.textLabel.font = [MDCTypography body2Font];
+      footerCell.textLabel.textColor = [[MDCPalette greyPalette] tint600];
+      footerCell.textLabel.shadowColor = nil;  // No shadow.
+      footerCell.horizontalPadding = kFooterCellHorizontalPadding;
+      break;
+    }
     default:
       break;
   }