First cut of JS closure compiler use for VR HTML UI.

chrome/browser/resources/vr_shell/vr_shell_ui.js

Index: chrome/browser/resources/vr_shell/vr_shell_ui.js
diff --git a/chrome/browser/resources/vr_shell/vr_shell_ui.js b/chrome/browser/resources/vr_shell/vr_shell_ui.js
index 3c8b7c8213cbb7858663b0615d6b49af7b2cdf66..bcb95ab4cfa333aedf008a1d5f8c99dd9fa1a398 100644
--- a/chrome/browser/resources/vr_shell/vr_shell_ui.js
+++ b/chrome/browser/resources/vr_shell/vr_shell_ui.js
@@ -122,6 +122,9 @@ var vrShellUi = (function() {
 
   class Controls {
     constructor(contentQuadId) {
+      this.enabled = false;
+      this.reloadUiEnabled = false;
+
       this.buttons = [];
       let descriptors = [
           ['#back', function() {
@@ -167,6 +170,10 @@ var vrShellUi = (function() {
       update.setVisible(false);
       update.setScale(2.2, 2.2, 1);
       update.setTranslation(0, -0.6, 0.3);
+
+      // The closure compiler should barf on this...
+      update.setTranslation(0, -0.6, 'cat');

[cjgrant, 2016/12/21 17:10:50]

This is what I was playing with:
- If I make a call like this from within vr_shell_ui_api.js, it complains about
type.
- If I break the name of this function, and try calling xSetTranslation(), it
complains (ie. it knows what the update class offers).
- But, this call works fine.

+
       update.setAnchoring(api.XAnchoring.XNONE, api.YAnchoring.YBOTTOM);
       scene.updateElement(this.reloadUiButton.uiElementId, update);
     }
@@ -198,6 +205,10 @@ var vrShellUi = (function() {
       /** @const */ var DISTANCE = 0.7;
       /** @const */ var ANGLE_UP = 16.3 * Math.PI / 180.0;
 
+      this.enabled = false;
+      this.secure = false;
+      this.secureOriginTimer = null;
+
       // Permanent WebVR security warning. This warning is shown near the top of
       // the field of view.
       this.webVrSecureWarning = new DomUiElement('#webvr-not-secure-permanent');
@@ -271,9 +282,11 @@ var vrShellUi = (function() {
     constructor(contentQuadId) {
       this.domUiElement = new DomUiElement('#omni-container');
       this.enabled = false;
+      this.loading = false;
       this.level = 0;
       this.visibilityTimeout = 0;
       this.visibilityTimer = null;
+      this.visibleAfterTransition = false;
       this.nativeState = {};
 
       // Initially invisible.