Typecheck JS files for chrome://extensions

ui/webui/resources/js/cr/ui/list.js

Index: ui/webui/resources/js/cr/ui/list.js
diff --git a/ui/webui/resources/js/cr/ui/list.js b/ui/webui/resources/js/cr/ui/list.js
index 91df98de53466534e19737e5a41693d7f65864bd..a820b3ad163e51fc57346b7b7cff7fbcc7e11eb5 100644
--- a/ui/webui/resources/js/cr/ui/list.js
+++ b/ui/webui/resources/js/cr/ui/list.js
@@ -21,7 +21,6 @@ cr.define('cr.ui', function() {
    * false if the mouseevent was generated over a border or a scrollbar.
    * @param {!HTMLElement} el The element to test the event with.
    * @param {!Event} e The mouse event.
-   * @param {boolean} Whether the mouse event was inside the viewport.

[Dan Beam, 2014/08/21 18:27:48]

this should be @return

[Vitaly Pavlenko, 2014/08/22 01:43:41]

Done.

    */
   function inViewport(el, e) {
     var rect = el.getBoundingClientRect();
@@ -53,11 +52,11 @@ cr.define('cr.ui', function() {
      * is needed. Note that lead item is allowed to have a different height, to
      * accommodate lists where a single item at a time can be expanded to show
      * more detail.
-     * @type {{height: number, marginTop: number, marginBottom:number,
-     *     width: number, marginLeft: number, marginRight:number}}
+     * @type {?{height: number, marginTop: number, marginBottom: number,
+     *     width: number, marginLeft: number, marginRight: number}}
      * @private
      */
-    measured_: undefined,
+    measured_: null,
 
     /**
      * Whether or not the list is autoexpanding. If true, the list resizes
@@ -85,14 +84,13 @@ cr.define('cr.ui', function() {
 
     /**
      * Function used to create grid items.
-     * @type {function(): !ListItem}
+     * @type {function(new:cr.ui.ListItem, string)}
      * @private
      */
     itemConstructor_: cr.ui.ListItem,
 
     /**
      * Function used to create grid items.

[Dan Beam, 2014/08/21 18:27:48]

* @type {function(new:cr.ui.ListItem, string)}

[Vitaly Pavlenko, 2014/08/22 01:43:41]

Done.

-     * @type {function(): !ListItem}
      */
     get itemConstructor() {
       return this.itemConstructor_;
@@ -242,7 +240,7 @@ cr.define('cr.ui', function() {
 
     /**
      * Convenience alias for selectionModel.selectedItems
-     * @type {!Array<*>}
+     * @type {!Array.<*>}
      */
     get selectedItems() {
       var indexes = this.selectionModel.selectedIndexes;
@@ -313,7 +311,8 @@ cr.define('cr.ui', function() {
       this.selectionModel = new ListSelectionModel(length);
 
       this.addEventListener('dblclick', this.handleDoubleClick_);
-      this.addEventListener('mousedown', handleMouseDown);
+      this.addEventListener('mousedown', /** @type {function(Event)} */(
+          handleMouseDown));
       this.addEventListener('dragstart', handleDragStart, true);
       this.addEventListener('mouseup', this.handlePointerDownUp_);
       this.addEventListener('keydown', this.handleKeyDown);
@@ -380,7 +379,7 @@ cr.define('cr.ui', function() {
     },
 
     /**
-     * @return {{height: number, width: number}} The height and width
+     * @return {?{height: number, width: number}} The height and width
      *     of default item, measuring it if necessary.
      * @private
      */
@@ -397,8 +396,8 @@ cr.define('cr.ui', function() {
      * @param {ListItem=} opt_item The list item to use to do the measuring. If
      *     this is not provided an item will be created based on the first value
      *     in the model.
-     * @return {{height: number, marginTop: number, marginBottom:number,
-     *     width: number, marginLeft: number, marginRight:number}}
+     * @return {?{height: number, marginTop: number, marginBottom: number,
+     *     width: number, marginLeft: number, marginRight: number}}
      *     The height and width of the item, taking
      *     margins into account, and the top, bottom, left and right margins
      *     themselves.
@@ -406,7 +405,7 @@ cr.define('cr.ui', function() {
     measureItem: function(opt_item) {
       var dataModel = this.dataModel;
       if (!dataModel || !dataModel.length)
-        return 0;
+        return null;
       var item = opt_item || this.cachedMeasuredItem_ ||
           this.createItem(dataModel.item(0));
       if (!opt_item) {
@@ -462,7 +461,7 @@ cr.define('cr.ui', function() {
       if (this.disabled)
         return;
 
-      var target = e.target;
+      var target = /** @type {HTMLElement} */(e.target);
 
       target = this.getListItemAncestor(target);

[Dan Beam, 2014/08/21 18:27:48]

nit: instead of reusing a var here, i'd say change

  target = ...;

to

  var ancestor = ...;

[Vitaly Pavlenko, 2014/08/22 01:43:41]

Done.

       if (target)
@@ -478,7 +477,7 @@ cr.define('cr.ui', function() {
       if (this.disabled)
         return;
 
-      var target = e.target;
+      var target = /** @type {HTMLElement} */(e.target);
 
       // If the target was this element we need to make sure that the user did
       // not click on a border or a scrollbar.
@@ -513,7 +512,7 @@ cr.define('cr.ui', function() {
      * @private
      */
     handleElementBlur_: function(e) {
-      if (!this.contains(e.relatedTarget))
+      if (!this.contains(assertInstanceof(e.relatedTarget, Element)))
         this.hasElementFocus = false;
     },
 
@@ -521,26 +520,23 @@ cr.define('cr.ui', function() {
      * Returns the list item element containing the given element, or null if
      * it doesn't belong to any list item element.
      * @param {HTMLElement} element The element.
-     * @return {ListItem} The list item containing |element|, or null.
+     * @return {cr.ui.ListItem} The list item containing |element|, or null.
      */
     getListItemAncestor: function(element) {
       var container = element;
       while (container && container.parentNode != this) {
         container = container.parentNode;
       }
-      return container;
+      return assertInstanceof(container, cr.ui.ListItem);
     },
 
     /**
      * Handle a keydown event.
      * @param {Event} e The keydown event.
-     * @return {boolean} Whether the key event was handled.
      */
     handleKeyDown: function(e) {
-      if (this.disabled)
-        return;
-
-      return this.selectionController_.handleKeyDown(e);
+      if (!this.disabled)
+        this.selectionController_.handleKeyDown(e);
     },
 
     /**
@@ -554,7 +550,7 @@ cr.define('cr.ui', function() {
     /**
      * Callback from the selection model. We dispatch {@code change} events
      * when the selection changes.
-     * @param {!Event} e Event with change info.
+     * @param {!Event} ce Event with change info.
      * @private
      */
     handleOnChange_: function(ce) {
@@ -606,7 +602,7 @@ cr.define('cr.ui', function() {
           var self = this;
           window.setTimeout(function() {
             self.scrollIndexIntoView(pe.newValue);
-          });
+          }, 0);
         }
       }
     },
@@ -801,6 +797,7 @@ cr.define('cr.ui', function() {
      * @return {!ListItem} The newly created list item.
      */
     createItem: function(value) {
+      assert(typeof value === "string");

[Dan Beam, 2014/08/21 18:27:48]

assertInstanceOf(value, string);

[Vitaly Pavlenko, 2014/08/22 01:43:41]

Unfortunately, no. "string" is not defined, and
    
    "a" instanceof String

if false.

       var item = new this.itemConstructor_(value);
       item.label = value;
       item.id = this.uniqueIdPrefix_ + '-' + this.nextUniqueIdSuffix_++;
@@ -1062,7 +1059,7 @@ cr.define('cr.ui', function() {
         this.firstIndex_ = 0;
         this.lastIndex_ = 0;
         this.remainingSpace_ = this.clientHeight != 0;
-        this.mergeItems(0, 0, {}, {});
+        this.mergeItems(0, 0);
         return;
       }
 
@@ -1276,10 +1273,11 @@ cr.define('cr.ui', function() {
 
   /**
    * Mousedown event handler.
-   * @this {List}
+   * @this {cr.ui.List}
    * @param {MouseEvent} e The mouse event object.
    */
   function handleMouseDown(e) {
+    e.target = /** @type {!HTMLElement} */(e.target);
     var listItem = this.getListItemAncestor(e.target);
     var wasSelected = listItem && listItem.selected;
     this.handlePointerDownUp_(e);
@@ -1307,10 +1305,11 @@ cr.define('cr.ui', function() {
    * Dragstart event handler.
    * If there is an item at starting position of drag operation and the item
    * is not selected, select it.
-   * @this {List}
-   * @param {MouseEvent} e The event object for 'dragstart'.
+   * @this {cr.ui.List}
+   * @param {Event} e The event object for 'dragstart'.
    */
   function handleDragStart(e) {
+    e = /** @type {MouseEvent} */(e);
     var element = e.target.ownerDocument.elementFromPoint(e.clientX, e.clientY);
     var listItem = this.getListItemAncestor(element);
     if (!listItem)