[iOS] Add experimental new keyboard accessory view.

ios/chrome/browser/ui/toolbar/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_KEYBOARD_ACCESSORY_VIEW_H_
 #define IOS_CHROME_BROWSER_UI_TOOLBAR_KEYBOARD_ACCESSORY_VIEW_H_
 
 #import <UIKit/UIKIt.h>
 
-// Delegate protocol for the KeyboardAccessoryView.
-@protocol KeyboardAccessoryViewDelegate
-
-// Notifies the delegate that the Voice Search button was pressed.
-- (void)keyboardAccessoryVoiceSearchTouchDown;
-
-// Notifies the delegate that a touch up occured in the the Voice Search button.
-- (void)keyboardAccessoryVoiceSearchTouchUpInside;
-
-// Notifies the delegate that a key with the title |title| was pressed.
-- (void)keyPressed:(NSString*)title;
-
-@end
-
-typedef NS_ENUM(NSInteger, KeyboardAccessoryViewMode) {
-  VOICE_SEARCH = 0,
-  KEY_SHORTCUTS
-};
+#import "ios/chrome/browser/ui/toolbar/keyboard_accessory_view_protocol.h"
 
 // Accessory View above the keyboard.
 // Supports two modes: one where a Voice Search button is shown, and one where
 // a list of buttons based on |buttonTitles| is shown.
 // The default mode is the Voice Search mode.
-@interface KeyboardAccessoryView : UIInputView<UIInputViewAudioFeedback>
+@interface KeyboardAccessoryView
+    : UIInputView<KeyboardAccessoryViewProtocol, UIInputViewAudioFeedback>
 
 // Designated initializer. |buttonTitles| lists the titles of the buttons shown
 // in the KEY_SHORTCUTS mode. Can be nil or empty. |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;
 
-// The mode in which the KeyboardAccessoryView is in.
-@property(nonatomic) KeyboardAccessoryViewMode mode;
-
 @end
 
 #endif  // IOS_CHROME_BROWSER_UI_TOOLBAR_KEYBOARD_ACCESSORY_VIEW_H_