Typecheck some of ui/webui/resources/js/ with Closure compiler.

ui/webui/resources/js/chromeos/ui_account_tweaks.js

 // 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.
 
 /**
  * @fileoverview This file contains methods that allow to tweak
  * internal page UI based on the status of current user (owner/user/guest).
  * It is assumed that required data is passed via i18n strings
  * (using loadTimeData dictionary) that are filled with call to
  * AddAccountUITweaksLocalizedValues in ui_account_tweaks.cc.
@@ skipping 57 matching lines @@
    */
   UIAccountTweaks.applySessionTypeVisibility_ = function(document,
                                                          sessionType) {
     var elements = document.querySelectorAll('['+ sessionType +'-visibility]');
     for (var i = 0; i < elements.length; i++) {
       var element = elements[i];
       var visibility = element.getAttribute(sessionType +'-visibility');
       if (visibility == 'hidden')
         element.hidden = true;
       else if (visibility == 'disabled')
-        UIAccountTweaks.disableElementsForSessionType(element, sessionType);
+        UIAccountTweaks.disableNodeForSessionType(element, sessionType);
     }
   }
 
   /**
    * Updates specific visibility of elements for Guest session in ChromeOS.
    * Calls applySessionTypeVisibility_ method.
    *
    * @param {Document} document Document that should processed.
    */
   UIAccountTweaks.applyGuestSessionVisibility = function(document) {
     if (!cr.isChromeOS || !UIAccountTweaks.loggedInAsGuest())
       return;
     UIAccountTweaks.applySessionTypeVisibility_(document, SESSION_TYPE_GUEST);
   }
 
   /**
    * Updates specific visibility of elements for Public account session in
    * ChromeOS. Calls applySessionTypeVisibility_ method.
    *
    * @param {Document} document Document that should processed.
    */
   UIAccountTweaks.applyPublicSessionVisibility = function(document) {
     if (!cr.isChromeOS || !UIAccountTweaks.loggedInAsPublicAccount())
       return;
     UIAccountTweaks.applySessionTypeVisibility_(document, SESSION_TYPE_PUBLIC);
   }
 
   /**
-   * Disables and marks page elements for specified session type.
-   * Adds #-disabled css class to all elements within given subtree,
-   * disables interactive elements (input/select/button), and removes href
-   * attribute from <a> elements.
+   * Disables and marks page nodes for specified session type.
+   * Adds #-disabled css class to all nodes within given subtree,
+   * disables interactive nodes (input/select/button), and removes href
+   * attribute from <a> nodes.
    *
-   * @param {Element} element Root element of DOM subtree that should be
-   *     disabled.
+   * @param {!Node} node Root node of DOM subtree that should be disabled.

[arv (Not doing code reviews), 2014/07/24 16:44:24]

!Element was more correct. Here is a case where the type system is doing us a
disservice.

[Dan Beam, 2014/07/25 01:52:32]

see what you think of updated changes

    * @param {string} sessionType session type specificator.
    */
-  UIAccountTweaks.disableElementsForSessionType = function(element,
-                                                           sessionType) {
-    UIAccountTweaks.disableElementForSessionType_(element, sessionType);
+  UIAccountTweaks.disableNodeForSessionType = function(node, sessionType) {
+    UIAccountTweaks.disableNodeForSessionType_(node, sessionType);
 
     // Walk the tree, searching each ELEMENT node.
-    var walker = document.createTreeWalker(element,
+    var walker = document.createTreeWalker(node,
                                            NodeFilter.SHOW_ELEMENT,
                                            null,
                                            false);
 
-    var node = walker.nextNode();
-    while (node) {
-      UIAccountTweaks.disableElementForSessionType_(node, sessionType);
-      node = walker.nextNode();
+    var temp = walker.nextNode();
+    while (temp) {
+      UIAccountTweaks.disableNodeForSessionType_(temp, sessionType);
+      temp = walker.nextNode();
     }
   };
 
   /**
-   * Disables single element for given session type.
+   * Disables single node for given session type.
    * Adds *sessionType*-disabled css class, adds disabled attribute for
-   * appropriate elements (input/select/button), and removes href attribute from
-   * <a> element.
+   * appropriate nodes (input/select/button), and removes href attribute from
+   * <a> node.
    *
+   * @param {Node} node Node to disable.
+   * @param {string} sessionType account session Type specificator.
    * @private
-   * @param {Element} element Element that should be disabled.
-   * @param {string} sessionType account session Type specificator.
    */
-  UIAccountTweaks.disableElementForSessionType_ = function(element,
-                                                           sessionType) {
-    element.classList.add(sessionType + '-disabled');
-    if (element.nodeName == 'INPUT' ||
-        element.nodeName == 'SELECT' ||
-        element.nodeName == 'BUTTON')
-      element.disabled = true;
-    if (element.nodeName == 'A') {
-      element.onclick = function() {
-        return false;
-      };
-    }
+  UIAccountTweaks.disableNodeForSessionType_ = function(node, sessionType) {
+    node.classList.add(sessionType + '-disabled');

[arv (Not doing code reviews), 2014/07/24 16:44:24]

Node does not have classList property. It is a property of Element so this
should cause a type error.

[Dan Beam, 2014/07/25 01:52:32]

that's what i thought as well, but it didn't.  i think it's just those externs
where someone threw all the properties they could find onto object or
something... either way, it's now !Element.

+
+    if (/^(INPUT|SELECT|BUTTON)$/.test(node.nodeName))

[arv (Not doing code reviews), 2014/07/24 16:44:24]

If you are refactoring this a switch would be the cleanest (and fastest).

[Dan Beam, 2014/07/25 01:52:32]

reverted

+      node.disabled = true;

[arv (Not doing code reviews), 2014/07/24 16:44:24]

Node does not have a disabled property. Is the type checker not working or are
the externs just wrong?

[Dan Beam, 2014/07/25 01:52:32]

externs

+    else if (node.nodeName == 'A')
+      node.onclick = function() { return false; };
   };
 
   // Export
   return {
     UIAccountTweaks: UIAccountTweaks
   };
 
 });