Make views Slider accessible on Chrome OS

chrome/browser/accessibility/accessibility_extension_api_constants.h

 // Copyright (c) 2012 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.
 
 // Constants used to for the Accessibility API.
 
 #ifndef CHROME_BROWSER_ACCESSIBILITY_ACCESSIBILITY_EXTENSION_API_CONSTANTS_H_
 #define CHROME_BROWSER_ACCESSIBILITY_ACCESSIBILITY_EXTENSION_API_CONSTANTS_H_
 #pragma once
 
 namespace extension_accessibility_api_constants {
 
 // Keys.
 extern const char kTypeKey[];
 extern const char kNameKey[];
 extern const char kContextKey[];
 extern const char kDetailsKey[];
 extern const char kValueKey[];
 extern const char kPasswordKey[];
 extern const char kItemCountKey[];
 extern const char kItemIndexKey[];
 extern const char kSelectionStartKey[];
 extern const char kSelectionEndKey[];
 extern const char kCheckedKey[];
 extern const char kHasSubmenuKey[];
 extern const char kMessageKey[];
+extern const char kStringValueKey[];
 
 // Events.
 extern const char kOnWindowOpened[];
 extern const char kOnWindowClosed[];
 extern const char kOnControlFocused[];
 extern const char kOnControlAction[];
 extern const char kOnTextChanged[];
 extern const char kOnMenuOpened[];
 extern const char kOnMenuClosed[];
 
 // Types of controls that can receive accessibility events
 extern const char kTypeButton[];
 extern const char kTypeCheckbox[];
 extern const char kTypeComboBox[];
 extern const char kTypeLink[];
 extern const char kTypeListBox[];
 extern const char kTypeMenu[];
 extern const char kTypeMenuItem[];
 extern const char kTypeRadioButton[];
+extern const char kTypeSlider[];
 extern const char kTypeTab[];
 extern const char kTypeTextBox[];
 extern const char kTypeVolume[];
 extern const char kTypeWindow[];
 
 };  // namespace extension_accessibility_api_constants
 
 #endif  // CHROME_BROWSER_ACCESSIBILITY_ACCESSIBILITY_EXTENSION_API_CONSTANTS_H_