Typecheck JS files for chrome://history

ui/webui/resources/js/cr/ui/alert_overlay.js

Index: ui/webui/resources/js/cr/ui/alert_overlay.js
diff --git a/ui/webui/resources/js/cr/ui/alert_overlay.js b/ui/webui/resources/js/cr/ui/alert_overlay.js
index 76ec5014d39d521eb6880cd82d850361a1abb954..594dbb83a584b38de936707a1b92c7a52ec0f4fa 100644
--- a/ui/webui/resources/js/cr/ui/alert_overlay.js
+++ b/ui/webui/resources/js/cr/ui/alert_overlay.js
@@ -16,8 +16,8 @@ cr.define('alertOverlay', function() {
   var cancelButton;
 
   function initialize(e) {
-    okButton = $('alertOverlayOk');
-    cancelButton = $('alertOverlayCancel');
+    okButton = /** @type {HTMLButtonElement} */($('alertOverlayOk'));

[Dan Beam, 2014/08/19 00:31:53]

why do these need to be buttons?

[Vitaly Pavlenko, 2014/08/19 18:30:27]

Done.

+    cancelButton = /** @type {HTMLButtonElement} */($('alertOverlayCancel'));
 
     // The callbacks are set to the callbacks provided in show(). Clear them
     // out when either is clicked.
@@ -46,9 +46,9 @@ cr.define('alertOverlay', function() {
    *     no button is shown.
    * @param {string=} cancelTitle The title of the cancel button. If undefined
    *     or empty, no button is shown.
-   * @param {function=} okCallback A function to be called when the user presses
-   *     the ok button. Can be undefined if |okTitle| is falsey.
-   * @param {function=} cancelCallback A function to be called when the user
+   * @param {function()=} okCallback A function to be called when the user

[Dan Beam, 2014/08/19 00:31:53]

add opt_ prefix

[Vitaly Pavlenko, 2014/08/19 18:30:27]

Done.

+   *     presses the ok button. Can be undefined if |okTitle| is falsey.
+   * @param {function()=} cancelCallback A function to be called when the user
    *     presses the cancel button. Can be undefined if |cancelTitle| is falsey.
    */
   function setValues(