Added basic accessibility to TreeView.

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",
     "compiler_options": {
       "implemented_in": "chrome/browser/accessibility/accessibility_extension_api.h"
     },
@@ skipping 76 matching lines @@
         "type": "object",
         "description": "Information about the state of a text box.",
         "properties": {
           "value": {"type": "string", "description": "The value of the text box - the entered text."},
           "isPassword": {"type": "boolean", "description": "True if this control contains password text whose contents should be obscured."},
           "selectionStart": {"type": "integer", "description": "The index of the character where the selection starts, if this control contains editable text."},
           "selectionEnd": {"type": "integer", "description": "The index of the character where the selection ends, if this control contains editable text."}
         }
       },
       {
+        "id": "TreeDetails",
+        "type": "object",
+        "description": "Information about the state of a tree control.",
+        "properties": {
+        }
+      },
+      {
+        "id": "TreeItemDetails",
+        "type": "object",
+        "description": "Information about a selected tree control item.",
+        "properties": {
+          "itemDepth": {"type": "integer", "description": "The 0-based depth of this tree item."},
+          "itemCount": {"type": "integer", "description": "The number of items in the current depth."},
+          "itemIndex": {"type": "integer", "description": "The 0-based index of this tree item at the current tree depth."},
+          "childrenCount": {"type": "integer", "description": "The number of children of the current tree item."},
+          "isItemExpanded": {"type": "boolean", "description": "True if this if this tree item is expanded."}
+        }
+      },
+      {
         "id": "AlertInfo",
         "type": "object",
         "description": "Information about an alert",
         "properties": {
           "message": {
             "type": "string",
             "description": "The message the alert is showing."
           }
         }
       },
       {
         "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": ["alert", "button", "checkbox", "combobox", "link", "menu", "menuitem", "radiobutton", "slider", "tab", "textbox", "window"]
+            "enum": ["alert", "button", "checkbox", "combobox", "link", "menu", "menuitem", "radiobutton", "slider", "tab", "textbox", "tree", "treeitem", "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" }
+              { "$ref": "TextBoxDetails" },
+              { "$ref": "TreeDetails" },
+              { "$ref": "TreeItemDetails" }
             ]
           }
         }
       }
     ],
     "functions": [
       {
         "name": "setAccessibilityEnabled",
         "type": "function",
         "description": "Enables or disables the accessibility extension api. This must be set to true before event listeners or getFocusedControl will work.",
@@ skipping 159 matching lines @@
           {
             "type": "boolean",
             "name": "makeAnnouncements",
             "description": "Whether to make introductory announcements."
           }
         ]
       }
     ]
   }
 ]