Revert of Revert "Typecheck JS files for chrome://extensions"

chrome/browser/resources/extensions/extension_command_list.js

Index: chrome/browser/resources/extensions/extension_command_list.js
diff --git a/chrome/browser/resources/extensions/extension_command_list.js b/chrome/browser/resources/extensions/extension_command_list.js
index 2c411d3a5fcdc0188ab6a89f6624f8888183211f..1f92c19cfda5f3b732e0abe71f252d58ce4dd36f 100644
--- a/chrome/browser/resources/extensions/extension_command_list.js
+++ b/chrome/browser/resources/extensions/extension_command_list.js
@@ -1,6 +1,16 @@
 // Copyright (c) 2012 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.
+
+/** @typedef {{active: boolean,
+ *             command_name: string,
+ *             description: string,
+ *             extension_action: boolean,
+ *             extension_id: string,
+ *             global: boolean,
+ *             keybinding: string}}
+ */
+var ExtensionCommand;
 
 cr.define('options', function() {
   'use strict';
@@ -9,7 +19,7 @@
    * Creates a new list of extension commands.
    * @param {Object=} opt_propertyBag Optional properties.
    * @constructor
-   * @extends {cr.ui.div}
+   * @extends {HTMLDivElement}
    */
   var ExtensionCommandList = cr.ui.define('div');
 
@@ -45,7 +55,7 @@
    * Returns whether the passed in |keyCode| is a valid extension command
    * char or not. This is restricted to A-Z and 0-9 (ignoring modifiers) at
    * the moment.
-   * @param {int} keyCode The keycode to consider.
+   * @param {number} keyCode The keycode to consider.
    * @return {boolean} Returns whether the char is valid.
    */
   function validChar(keyCode) {
@@ -139,7 +149,7 @@
    * Returns whether the passed in |keyCode| require modifiers. Currently only
    * "MediaNextTrack", "MediaPrevTrack", "MediaStop", "MediaPlayPause" are
    * required to be used without any modifier.
-   * @param {int} keyCode The keycode to consider.
+   * @param {number} keyCode The keycode to consider.
    * @return {Modifiers} Returns whether the keycode require modifiers.
    */
   function modifiers(keyCode) {
@@ -174,7 +184,7 @@
      * While capturing, this records the current (last) keyboard event generated
      * by the user. Will be |null| after capture and during capture when no
      * keyboard event has been generated.
-     * @type: {keyboard event}.
+     * @type {KeyboardEvent}.
      * @private
      */
     currentKeyEvent_: null,
@@ -182,7 +192,7 @@
     /**
      * While capturing, this keeps track of the previous selection so we can
      * revert back to if no valid assignment is made during capture.
-     * @type: {string}.
+     * @type {string}.
      * @private
      */
     oldValue_: '',
@@ -190,7 +200,7 @@
     /**
      * While capturing, this keeps track of which element the user asked to
      * change.
-     * @type: {HTMLElement}.
+     * @type {HTMLElement}.
      * @private
      */
     capturingElement_: null,
@@ -227,7 +237,8 @@
     /**
      * Synthesizes and initializes an HTML element for the extension command
      * metadata given in |command|.
-     * @param {Object} command A dictionary of extension command metadata.
+     * @param {ExtensionCommand} command A dictionary of extension command
+     *     metadata.
      * @private
      */
     createNodeForCommand_: function(command) {
@@ -245,8 +256,7 @@
                                     this.startCapture_.bind(this));
       shortcutNode.addEventListener('focus', this.handleFocus_.bind(this));
       shortcutNode.addEventListener('blur', this.handleBlur_.bind(this));
-      shortcutNode.addEventListener('keydown',
-                                    this.handleKeyDown_.bind(this));
+      shortcutNode.addEventListener('keydown', this.handleKeyDown_.bind(this));
       shortcutNode.addEventListener('keyup', this.handleKeyUp_.bind(this));
       if (!command.active) {
         shortcutNode.textContent =
@@ -312,7 +322,7 @@
           shortcutNode.parentElement.querySelector('.command-clear');
       commandClear.hidden = true;
 
-      this.capturingElement_ = event.target;
+      this.capturingElement_ = /** @type {HTMLElement} */(event.target);
     },
 
     /**
@@ -384,6 +394,7 @@
      * @private
      */
     handleKeyDown_: function(event) {
+      event = /** @type {KeyboardEvent} */(event);
       if (event.keyCode == keyEscape) {
         // Escape cancels capturing.
         this.endCapture_(event);
@@ -412,6 +423,7 @@
      * @private
      */
     handleKeyUp_: function(event) {
+      event = /** @type {KeyboardEvent} */(event);
       if (event.keyCode == keyTab) {
         // Allow tab propagation for keyboard navigation.
         return;
@@ -439,7 +451,7 @@
 
     /**
      * A general key handler (used for both KeyDown and KeyUp).
-     * @param {Event} event The keyboard event to consider.
+     * @param {KeyboardEvent} event The keyboard event to consider.
      * @private
      */
     handleKey_: function(event) {
@@ -523,8 +535,7 @@
      * extension id and a command name.
      * @param {string} namespace   The namespace to prepend the id with.
      * @param {string} id          The id to parse.
-     * @return {object} The parsed id, as an object with two members:
-     *                  extensionID and commandName.
+     * @return {{extensionId: string, commandName: string}} The parsed id.
      * @private
      */
     parseElementId_: function(namespace, id) {