Control visibility of 2D VR menu buttons using native state.

chrome/browser/resources/vr_shell/vr_shell_ui_api.js

Index: chrome/browser/resources/vr_shell/vr_shell_ui_api.js
diff --git a/chrome/browser/resources/vr_shell/vr_shell_ui_api.js b/chrome/browser/resources/vr_shell/vr_shell_ui_api.js
index 976b616aa26e65e61e1166b51ab6887e442ba53b..018972ccaf2c5f26f42f6162a2d85d8080b07aba 100644
--- a/chrome/browser/resources/vr_shell/vr_shell_ui_api.js
+++ b/chrome/browser/resources/vr_shell/vr_shell_ui_api.js
@@ -74,6 +74,16 @@ var api = (function() {
   });
 
   /**
+   * Enumeration of modes that can be specified by the native side.
+   * @enum {number}
+   * @const
+   */
+  var Mode = Object.freeze({
+    'STANDARD': 0,
+    'WEB_VR': 1
+  });
+
+  /**
    * Triggers an Action.
    */
   function doAction(action) {
@@ -268,6 +278,7 @@ var api = (function() {
     Easing: Easing,
     Command: Command,
     Action: Action,
+    Mode: Mode,
     getContentElementId: getContentElementId,
     UiElement: UiElement,
     UiElementUpdate: UiElementUpdate,