Add 5 experimental accessibility features on Chrome OS.

chrome/common/extensions/api/accessibility_features.json

 // Copyright 2014 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": "accessibilityFeatures",
     "description": "Use the <code>chrome.accessibilityFeatures</code> API to manage Chrome's accessibility features. This API relies on the <a href='types#ChromeSetting'>ChromeSetting prototype of the type API</a> for getting and setting individual accessibility features. In order to get feature states the extension must request <code>accessibilityFeatures.read</code> permission. For modifying feature state, the extension needs <code>accessibilityFeatures.modify</code> permission. Note that <code>accessibilityFeatures.modify</code> does not imply <code>accessibilityFeatures.read</code> permission.",
     "properties": {
       "spokenFeedback": {
@@ skipping 31 matching lines @@
         "description":"<p><strong>ChromeOS only.</strong></p><p>Auto mouse click after mouse stops moving. The value indicates whether the feature is enabled or not. <code>get()</code> requires <code>accessibilityFeatures.read</code> permission. <code>set()</code> and <code>clear()</code> require <code>accessibilityFeatures.modify</code> permission.</p>",
         "value": ["autoclick", {"type": "boolean"}],
         "platforms": ["chromeos"]
       },
       "virtualKeyboard": {
         "$ref": "types.ChromeSetting",
         "description": "<p><strong>ChromeOS only.</strong></p><p>Virtual on-screen keyboard. The value indicates whether the feature is enabled or not. <code>get()</code> requires <code>accessibilityFeatures.read</code> permission. <code>set()</code> and <code>clear()</code> require <code>accessibilityFeatures.modify</code> permission.</p>",
         "value": ["virtualKeyboard", {"type": "boolean"}],
         "platforms": ["chromeos"]
       },
+      "caretHighlight": {
+        "$ref": "types.ChromeSetting",
+        "description": "<p><strong>ChromeOS only.</strong></p><p>Caret highlighting. The value indicates whether the feature is enabled or not. <code>get()</code> requires <code>accessibilityFeatures.read</code> permission. <code>set()</code> and <code>clear()</code> require <code>accessibilityFeatures.modify</code> permission.</p>",
+        "value": ["caretHighlight", {"type": "boolean"}],
+        "platforms": ["chromeos"]
+      },
+      "cursorHighlight": {
+        "$ref": "types.ChromeSetting",
+        "description": "<p><strong>ChromeOS only.</strong></p><p>Cursor highlighting. The value indicates whether the feature is enabled or not. <code>get()</code> requires <code>accessibilityFeatures.read</code> permission. <code>set()</code> and <code>clear()</code> require <code>accessibilityFeatures.modify</code> permission.</p>",
+        "value": ["cursorHighlight", {"type": "boolean"}],
+        "platforms": ["chromeos"]
+      },
+      "focusHighlight": {
+        "$ref": "types.ChromeSetting",
+        "description": "<p><strong>ChromeOS only.</strong></p><p>Focus highlighting. The value indicates whether the feature is enabled or not. <code>get()</code> requires <code>accessibilityFeatures.read</code> permission. <code>set()</code> and <code>clear()</code> require <code>accessibilityFeatures.modify</code> permission.</p>",
+        "value": ["focusHighlight", {"type": "boolean"}],
+        "platforms": ["chromeos"]
+      },
+      "selectToSpeak": {
+        "$ref": "types.ChromeSetting",
+        "description": "<p><strong>ChromeOS only.</strong></p><p>Select-to-speak. The value indicates whether the feature is enabled or not. <code>get()</code> requires <code>accessibilityFeatures.read</code> permission. <code>set()</code> and <code>clear()</code> require <code>accessibilityFeatures.modify</code> permission.</p>",
+        "value": ["selectToSpeak", {"type": "boolean"}],
+        "platforms": ["chromeos"]
+      },
+      "switchAccess": {
+        "$ref": "types.ChromeSetting",
+        "description": "<p><strong>ChromeOS only.</strong></p><p>Switch access. The value indicates whether the feature is enabled or not. <code>get()</code> requires <code>accessibilityFeatures.read</code> permission. <code>set()</code> and <code>clear()</code> require <code>accessibilityFeatures.modify</code> permission.</p>",
+        "value": ["switchAccess", {"type": "boolean"}],
+        "platforms": ["chromeos"]
+      },
       "animationPolicy": {
         "$ref": "types.ChromeSetting",
         "description": "<code>get()</code> requires <code>accessibilityFeatures.read</code> permission. <code>set()</code> and <code>clear()</code> require <code>accessibilityFeatures.modify</code> permission.",
         "value": [
           "animationPolicy", {
             "type": "string",
             "enum": [{
               "description": "Images are allowed to animate.",
               "name": "allowed"
             }, {
               "description": "Images are animated once.",
               "name": "once"
             }, {
               "description": "Images are not animated.",
               "name": "none"
             }]
           }
         ]
       }
     }
   }
 ]