Make views Slider accessible on Chrome OS

chrome/common/extensions/api/experimental.accessibility.json

 // 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.
 
 [
   {
     "namespace": "experimental.accessibility",
     "nodoc": true,
     "types": [
       {
         "id": "AccessibilityObject",
         "type": "object",
         "description": "Parent class for accessibility information about an object.",
         "properties": {
           "type": {
             "type": "string",
             "description": "The type of this object, which determines the contents of 'details'.",
-            "enum": ["button", "checkbox", "combobox", "link", "menu", "menuitem", "radiobutton", "tab", "textbox", "window"]
+            "enum": ["button", "checkbox", "combobox", "link", "menu", "menuitem", "radiobutton", "slider", "tab", "textbox", "window"]
           },
           "name": {
             "type": "string",
             "description": "The localized name of the object, like OK or Password. Do not rely on an exact string match because the text will be in the user's language and may change in the future."
           },
           "context": {
             "type": "string",
             "description": "The localized name of the context for the object, like the name of the surrounding toolbar or group of controls.",
             "optional": true
           },
           "details": {
             "description": "Other details like the state, depending on the type of object.",
             "optional": true,
             "choices": [
               { "$ref": "CheckboxDetails" },
               { "$ref": "ComboBoxDetails" },
               { "$ref": "MenuDetails" },
               { "$ref": "MenuItemDetails" },
               { "$ref": "RadioButtonDetails" },
+              { "$ref": "SliderDetails" },
               { "$ref": "TabDetails" },
               { "$ref": "TextBoxDetails" }
             ]
           }
         }
       },
       {
         "id": "CheckboxDetails",
         "type": "object",
         "description": "Information about the state of a checkbox.",
@@ skipping 42 matching lines @@
         "id": "RadioButtonDetails",
         "type": "object",
         "description": "Information about the state of a radio button.",
         "properties": {
           "isChecked": {"type": "boolean", "description": "True if this radio button is checked."},
           "itemCount": {"type": "integer", "description": "The number of radio buttons in this group."},
           "itemIndex": {"type": "integer", "description": "The 0-based index of this radio button in this group."}
         }
       },
       {
+        "id": "SliderDetails",
+        "type": "object",
+        "description": "Information about the state of a slider.",
+        "properties": {
+          "stringValue": {"type": "string", "description": "The value of the slider as a string."}
+        }
+      },
+      {
         "id": "TabDetails",
         "type": "object",
         "description": "Additional accessibility information about a tab.",
         "properties": {
           "itemCount": {"type": "integer", "description": "The number of tabs in this group."},
           "itemIndex": {"type": "integer", "description": "The 0-based index of this tab in this group."}
         }
       },
       {
         "id": "TextBoxDetails",
@@ skipping 156 matching lines @@
           {
             "$ref": "AccessibilityObject",
             "name": "menu",
             "description": "Information about the menu that was closed."
           }
         ]
       }
     ]
   }
 ]