[ios] Hide NTP tab bar for all form factors.

Bug: 805634
Cq-Include-Trybots: master.tryserver.chromium.mac:ios-simulator-cronet;master.tryserver.chromium.mac:ios-simulator-full-configs
Change-Id: Id3433625e9c8da612431181aeff11abbea6247aa
Reviewed-on: https://chromium-review.googlesource.com/893824Reviewed-by: Rohit Rao <rohitrao@chromium.org>
Commit-Queue: Justin Cohen <justincohen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#532990}

ios/chrome/browser/ui/ntp/new_tab_page_view.mm

@@ -69,7 +69,9 @@
 - (void)layoutSubviews {
   [super layoutSubviews];
 
-  self.tabBar.hidden = !self.tabBar.items.count;
+  // TODO(crbug.com/807330) Completely remove tabbar once
+  // IsUIRefreshPhase1Enabled is defaulted on.
+  self.tabBar.hidden = !self.tabBar.items.count || IsUIRefreshPhase1Enabled();
   if (self.tabBar.hidden) {
     self.contentView.frame = self.bounds;
   } else {