[Code cleanup]Remove webui virtual keyboard code

ui/keyboard/keyboard_constants.h

 // Copyright (c) 2013 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 UI_KEYBOARD_KEYBOARD_CONSTANTS_H_
 #define UI_KEYBOARD_KEYBOARD_CONSTANTS_H_
 
 #include "ui/keyboard/keyboard_export.h"
 
 namespace keyboard {
 
-// The URL of the keyboard WebUI.
-KEYBOARD_EXPORT extern const char kKeyboardWebUIURL[];
+// The URL of the keyboard extension.
+KEYBOARD_EXPORT extern const char kKeyboardURL[];
 
-// The host of the keyboard WebUI URL.
-KEYBOARD_EXPORT extern const char kKeyboardWebUIHost[];
+// The host of the keyboard extension URL.
+KEYBOARD_EXPORT extern const char kKeyboardHost[];
 
 }  // namespace keyboard
 
 #endif  //  UI_KEYBOARD_KEYBOARD_CONSTANTS_H_