Stop re-adding subviews to keyboard accessory view.

ios/chrome/browser/ui/toolbar/new_keyboard_accessory_view.h

 // 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.
 
 #ifndef IOS_CHROME_BROWSER_UI_TOOLBAR_NEW_KEYBOARD_ACCESSORY_VIEW_H_
 #define IOS_CHROME_BROWSER_UI_TOOLBAR_NEW_KEYBOARD_ACCESSORY_VIEW_H_
 
 #import <UIKit/UIKIt.h>
 
 #import "ios/chrome/browser/ui/toolbar/keyboard_accessory_view_protocol.h"
 
 // Accessory View above the keyboard.
 // Shows keys that are shortcuts to commonly used characters or strings,
 // and buttons to start Voice Search or a Camera Search.
-// Must only be used on iPhones as iPads have a different pattern regarding
-// keyboard shortcuts.
 @interface NewKeyboardAccessoryView
     : UIInputView<KeyboardAccessoryViewProtocol, UIInputViewAudioFeedback>
 
 // Designated initializer. |buttonTitles| lists the titles of the shortcut
 // buttons. |delegate| receives the various events triggered in the view. Not
 // retained, and can be nil.
 - (instancetype)initWithButtons:(NSArray<NSString*>*)buttonTitles
                        delegate:(id<KeyboardAccessoryViewDelegate>)delegate
     NS_DESIGNATED_INITIALIZER;
 
 - (instancetype)initWithCoder:(NSCoder*)aDecoder NS_UNAVAILABLE;
 
 - (instancetype)initWithFrame:(CGRect)frame
                inputViewStyle:(UIInputViewStyle)inputViewStyle NS_UNAVAILABLE;
 
 @end
 
 #endif  // IOS_CHROME_BROWSER_UI_TOOLBAR_NEW_KEYBOARD_ACCESSORY_VIEW_H_