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

chrome/browser/resources/vr_shell/vr_shell_ui_scene.js

 // Copyright 2016 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.
 
-var ui = (function() {
-  'use strict';
+var ui = new Object();

[Dan Beam, 2017/01/04 20:29:02]

don't invoke Object, just use {}

[cjgrant, 2017/01/04 21:23:17]

Thanks; I'll fix that in a follow-on change.

+
+/**
+ * The scene class assists in managing element and animations in the scene.
+ * It allows scene update commands to be queued in batches, and manages
+ * allocation of element and animation IDs.
+ *
+ * Examples:
+ *
+ * var scene = new ui.Scene();
+ *
+ * // Add an element.
+ * var el = new api.UiElement(100, 200, 50, 50);
+ * el.setSize(buttonWidth, buttonHeight);
+ *
+ * // Anchor it to the bottom of the content quad.
+ * el.setParentId(contentQuadId);
+ * el.setAnchoring(api.XAnchoring.XNONE, api.YAnchoring.YBOTTOM);
+ *
+ * // Place it just below the content quad edge.
+ * el.setTranslation(0, -0.2, 0.0);
+ *
+ * // Add it to the scene.
+ * var buttonId = scene.addElement(el);
+ * scene.flush();
+ *
+ * // Make the button twice as big.
+ * var update = new api.UiElementUpdate();
+ * update.setSize(bunttonWidth * 2, buttonHeight * 2);
+ * scene.updateElement(buttonId, update);
+ * scene.flush();
+ *
+ * // Animate the button size back to its original size, over 250 ms.
+ * var resize = new api.Animation(buttonId, 250);
+ * resize.setSize(buttonWidth, buttonHeight);
+ * scene.addAnimation(resize);
+ * scene.flush();
+ *
+ * @struct
+ */
+ui.Scene = class {
+
+  constructor() {
+    /** @private {number} */
+    this.idIndex = 1;
+    /** @private {Array<Object>} */
+    this.commands = [];
+    /** @private {!Set<number>} */
+    this.elements = new Set();
+    /** @private {!Object} */
+    this.animations = [];
+  }
 
   /**
-   * The scene class assists in managing element and animations in the scene.
-   * It allows scene update commands to be queued in batches, and manages
-   * allocation of element and animation IDs.
+   * Flush all queued commands to native.
+   */
+  flush() {
+    api.sendCommands(this.commands);
+    this.commands = [];
+  }
+
+  /**
+   * Add a new UiElement to the scene, returning the ID assigned.
+   * @param {api.UiElement} element
+   */
+  addElement(element) {
+    var id = this.idIndex++;
+    element.setId(id);
+    this.commands.push({
+      'type': api.Command.ADD_ELEMENT,
+      'data': element.properties
+    });
+    this.elements.add(id);
+    return id;
+  }
+
+  /**
+   * Update an existing element, according to a UiElementUpdate object.
+   * @param {number} id
+   * @param {api.UiElementUpdate} update
+   */
+  updateElement(id, update) {
+    // To-do:  Make sure ID exists.
+    update.setId(id);
+    this.commands.push({
+      'type': api.Command.UPDATE_ELEMENT,
+      'data': update.properties
+    });
+  }
+
+  /**
+   * Remove an element from the scene.
+   * @param {number} id
+   */
+  removeElement(id) {
+    // To-do: Make sure ID exists.
+    this.commands.push({
+      'type': api.Command.REMOVE_ELEMENT,
+      'data': {'id': id}
+    });
+    this.elements.delete(id);
+  }
+
+  /**
+   * Add a new Animation to the scene, returning the ID assigned.
+   * @param {api.Animation} animation
+   */
+  addAnimation(animation) {
+    var id = this.idIndex++;
+    animation.setId(id);
+    this.commands.push({
+      'type': api.Command.ADD_ANIMATION,
+      'data': animation
+    });
+    this.animations[id] = animation.meshId;
+    return id;
+  }
+
+  /**
+   * Remove an animation from the scene.
    *
-   * Examples:
+   * Note that animations are flushed when they complete and are not required
+   * to be removed. Also new animations of the same type will effectively
+   * override the original so there is no need to remove in that scenario
+   * either.
    *
-   * var scene = new ui.Scene();
-   *
-   * // Add an element.
-   * var el = new api.UiElement(100, 200, 50, 50);
-   * el.setSize(buttonWidth, buttonHeight);
-   *
-   * // Anchor it to the bottom of the content quad.
-   * el.setParentId(api.getContentElementId());
-   * el.setAnchoring(api.XAnchoring.XNONE, api.YAnchoring.YBOTTOM);
-   *
-   * // Place it just below the content quad edge.
-   * el.setTranslation(0, -0.2, 0.0);
-   *
-   * // Add it to the scene.
-   * var buttonId = scene.addElement(el);
-   * scene.flush();
-   *
-   * // Make the button twice as big.
-   * var update = new api.UiElementUpdate();
-   * update.setSize(bunttonWidth * 2, buttonHeight * 2);
-   * scene.updateElement(buttonId, update);
-   * scene.flush();
-   *
-   * // Animate the button size back to its original size, over 250 ms.
-   * var resize = new api.Animation(buttonId, 250);
-   * resize.setSize(buttonWidth, buttonHeight);
-   * scene.addAnimation(resize);
-   * scene.flush();
+   * @param {number} id
    */
-  class Scene {
+  removeAnimation(id) {
+    // To-do: Make sure ID exists.
+    this.commands.push({
+      'type': api.Command.REMOVE_ANIMATION,
+      'data': {'id': id, 'meshId': this.animations[id]}
+    });
+    delete this.animations[id];
+  }
 
-    constructor() {
-      this.idIndex = api.getContentElementId() + 1;
-      this.commands = [];
-      this.elements = new Set();
-      this.animations = {};
+  /**
+   * Purge all elements in the scene.
+   */
+  purge() {
+    var ids = Object.keys(this.animations);
+    for (let id_key of ids) {
+      var id = parseInt(id_key, 10);
+      this.removeAnimation(id);
     }
-
-    /**
-     * Flush all queued commands to native.
-     */
-    flush() {
-      api.sendCommands(this.commands);
-      this.commands = [];
+    var ids = this.elements.values();
+    for (let id of ids) {
+      this.removeElement(id);
     }
-
-    /**
-     * Add a new UiElement to the scene, returning the ID assigned.
-     */
-    addElement(element) {
-      var id = this.idIndex++;
-      element.id = id;
-      this.commands.push({
-        'type': api.Command.ADD_ELEMENT,
-        'data': element
-      });
-      this.elements.add(id);
-      return id;
-    }
-
-    /**
-     * Update an existing element, according to a UiElementUpdate object.
-     */
-    updateElement(id, update) {
-      // To-do:  Make sure ID exists.
-      update.id = id;
-      this.commands.push({
-        'type': api.Command.UPDATE_ELEMENT,
-        'data': update
-      });
-    }
-
-    /*
-     * Remove an element from the scene.
-     */
-    removeElement(id) {
-      // To-do: Make sure ID exists.
-      this.commands.push({
-        'type': api.Command.REMOVE_ELEMENT,
-        'data': {'id': id}
-      });
-      this.elements.delete(id);
-    }
-
-    /**
-     * Add a new Animation to the scene, returning the ID assigned.
-     */
-    addAnimation(animation) {
-      var id = this.idIndex++;
-      animation.id = id;
-      this.commands.push({
-        'type': api.Command.ADD_ANIMATION,
-        'data': animation
-      });
-      this.animations[id] = animation.meshId;
-      return id;
-    }
-
-    /*
-     * Remove an animation from the scene.
-     *
-     * Note that animations are flushed when they complete and are not required
-     * to be removed. Also new animations of the same type will effectively
-     * override the original so there is no need to remove in that scenario
-     * either.
-     */
-    removeAnimation(id) {
-      // To-do: Make sure ID exists.
-      this.commands.push({
-        'type': api.Command.REMOVE_ANIMATION,
-        'data': {'id': id, 'meshId': this.animations[id]}
-      });
-      delete this.animations[id];
-    }
-
-    /*
-     * Purge all elements in the scene.
-     */
-    purge() {
-      var ids = Object.keys(this.animations);
-      for (let id_key of ids) {
-        var id = parseInt(id_key);
-        this.removeAnimation(id);
-      }
-      var ids = this.elements.values();
-      for (let id of ids) {
-        this.removeElement(id);
-      }
-      this.flush();
-    }
-  };
-
-  return {
-    Scene: Scene,
-  };
-})();
+    this.flush();
+  }
+};