[iOS] Add experimental new 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.
+@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_