Implement ChromeVox Next menus.

chrome/browser/resources/chromeos/chromevox/manifest.json.jinja2

 {
 {%if key is defined %}
   "key": "{{key}}",
 {% endif %}
   "manifest_version": 2,
   "name": "__MSG_CHROMEVOX_NAME__",
   "version": "{{set_version}}",
   "description": "__MSG_CHROMEVOX_DESCRIPTION__",
 {% if is_guest_manifest == '1' %}
   "incognito": "split",
@@ skipping 42 matching lines @@
   "web_accessible_resources": [
     "chromevox/injected/api.js",
     "chromevox/injected/api_util.js",
     "chromevox/injected/mathjax.js",
     "chromevox/injected/mathjax_external_util.js"
   ],
   "automation": {
     "desktop": true
   },
   "commands": {
-    "nextElement": {
+    "nextObject": {
       "description": "__MSG_CHROMEVOX_NEXT_OBJECT__",
       "suggested_key": {
         "default": "Alt+Shift+Right"
       }
     },
-    "previousElement": {
+    "previousObject": {
       "description": "__MSG_CHROMEVOX_PREVIOUS_OBJECT__",
       "suggested_key": {
         "default": "Alt+Shift+Left"
       }
     },
     "doDefault": {
       "description": "__MSG_CHROMEVOX_PERFORM_DEFAULT_ACTION__",
       "suggested_key": {
         "default": "Alt+Shift+Space"
       }
@@ skipping 12 matching lines @@
     }
   },
   "options_page": "chromevox/background/options.html",
   "default_locale": "en",
   "icons": {
     "16": "images/chromevox-16.png",
     "48": "images/chromevox-48.png",
     "128": "images/chromevox-128.png"
   }
 }