[ios clean] Use dispatcher for showing TabStrip

ios/clean/chrome/browser/ui/tab_strip/tab_strip_toolbar.mm

 // Copyright 2017 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/clean/chrome/browser/ui/tab_strip/tab_strip_toolbar.h"
 
 #import "ios/chrome/browser/ui/icons/chrome_icon.h"
 #import "ios/clean/chrome/browser/ui/actions/tab_strip_actions.h"
 
 #if !defined(__has_feature) || !__has_feature(objc_arc)
@@ skipping 31 matching lines @@
   toolbar.layoutMarginsRelativeArrangement = YES;
   toolbar.layoutMargins = UIEdgeInsetsMake(0, 0, kSpacing, 0);
   toolbar.distribution = UIStackViewDistributionFillEqually;
   return toolbar;
 }
 
 - (UIButton*)closeButton {
   UIButton* button = [UIButton buttonWithType:UIButtonTypeSystem];
   [button setImage:[ChromeIcon closeIcon] forState:UIControlStateNormal];
   [button setTintColor:[UIColor whiteColor]];
+  // TODO(crbug.com/733453): Use dispatcher instead of responder chain.
   [button addTarget:nil
                 action:@selector(hideTabStrip:)
       forControlEvents:UIControlEventTouchUpInside];
   return button;
 }
 
 - (UIButton*)incognitoButton {
   UIButton* button = [UIButton buttonWithType:UIButtonTypeSystem];
   UIImage* image = [UIImage imageNamed:@"tabswitcher_incognito"];
   [button setImage:image forState:UIControlStateNormal];
   [button setTintColor:[UIColor whiteColor]];
   return button;
 }
 
 @end