Typecheck JS files for chrome://help before doing import transition

ui/webui/resources/js/cr/ui/focus_manager.js

Index: ui/webui/resources/js/cr/ui/focus_manager.js
diff --git a/ui/webui/resources/js/cr/ui/focus_manager.js b/ui/webui/resources/js/cr/ui/focus_manager.js
index c84277c93c26f89be806deeb87fb692bd24a69c3..c82ec30cc6961a8eaa55ea51e56d75280ab65d9a 100644
--- a/ui/webui/resources/js/cr/ui/focus_manager.js
+++ b/ui/webui/resources/js/cr/ui/focus_manager.js
@@ -29,7 +29,7 @@ cr.define('cr.ui', function() {
      * @private
      */
     isDescendantOf_: function(parent, child) {
-      return parent && !(parent === child) && parent.contains(child);
+      return !!parent && !(parent === child) && parent.contains(child);
     },
 
     /**
@@ -43,7 +43,7 @@ cr.define('cr.ui', function() {
 
     /**
      * Returns the elements on the page capable of receiving focus.
-     * @return {Array.Element} The focusable elements.
+     * @return {Array.<Element>} The focusable elements.
      */
     getFocusableElements_: function() {
       var focusableDiv = this.getFocusParent();
@@ -52,7 +52,9 @@ cr.define('cr.ui', function() {
       var treeWalker = document.createTreeWalker(
           focusableDiv,
           NodeFilter.SHOW_ELEMENT,
-          { acceptNode: function(node) {
+          /** @type {NodeFilter} */
+          ({
+            acceptNode: function(node) {
               var style = window.getComputedStyle(node);
               // Reject all hidden nodes. FILTER_REJECT also rejects these
               // nodes' children, so non-hidden elements that are descendants of
@@ -70,7 +72,7 @@ cr.define('cr.ui', function() {
               // Accept nodes that are non-hidden and focusable.
               return NodeFilter.FILTER_ACCEPT;
             }
-          },
+          }),
           false);
 
       var focusable = [];
@@ -153,6 +155,7 @@ cr.define('cr.ui', function() {
      * @private
      */
     onDocumentFocus_: function(event) {
+      event.target = /** @type {Element} */(event.target);

[Dan Beam, 2014/07/23 22:09:24]

this can be (and very well might be) a Document.  why can't we use EventTarget
instead?

[Vitaly Pavlenko, 2014/07/24 01:09:31]

Done.

       // If the element being focused is a descendant of the currently visible
       // page, focus is valid.
       if (this.isDescendantOf_(this.getFocusParent(), event.target)) {