[ios clean] Add placeholder for NTP bookmarks, chrome home and open tabs.

ios/chrome/browser/ui/ntp/recent_tabs/recent_tabs_panel_controller.mm

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #import "ios/chrome/browser/ui/ntp/recent_tabs/recent_tabs_panel_controller.h"
 
 #include <memory>
 
 #include "base/mac/scoped_nsobject.h"
 #include "components/browser_sync/profile_sync_service.h"
@@ skipping 160 matching lines @@
   CGFloat pixelsBelowFrame = contentHeight - offsetY - scrollViewHeight;
   CGFloat alpha = pixelsBelowFrame / kNewTabPageDistanceToFadeShadow;
   alpha = MIN(MAX(alpha, 0), 1);
   return alpha;
 }
 
 - (UIView*)view {
   return [_tableViewController view];
 }
 
+- (UIViewController*)viewController {
+  return _tableViewController;
+}
+
 #pragma mark - Private
 
 - (BOOL)isSignedIn {
   SigninManager* signin_manager =
       ios::SigninManagerFactory::GetForBrowserState(_browserState);
   return signin_manager->IsAuthenticated();
 }
 
 - (BOOL)isSyncTabsEnabled {
   DCHECK([self isSignedIn]);
@@ skipping 41 matching lines @@
   [_tableViewController refreshUserState:[self userSignedInState]];
 }
 
 #pragma mark - RecentTabsTableViewControllerDelegate
 
 - (void)recentTabsTableViewContentMoved:(UITableView*)tableView {
   [self.delegate updateNtpBarShadowForPanelController:self];
 }
 
 @end