Fix closing the Alert overlay

ui/webui/resources/js/cr/ui/page_manager/page_manager.js

Index: ui/webui/resources/js/cr/ui/page_manager/page_manager.js
diff --git a/ui/webui/resources/js/cr/ui/page_manager/page_manager.js b/ui/webui/resources/js/cr/ui/page_manager/page_manager.js
index 6f9f1cce3ffe6bd8bccb1c84cb3e3a46d359816e..0fd4a185cc605c6ef26c06c3e612d0b3c89d06b8 100644
--- a/ui/webui/resources/js/cr/ui/page_manager/page_manager.js
+++ b/ui/webui/resources/js/cr/ui/page_manager/page_manager.js
@@ -536,9 +536,14 @@ cr.define('cr.ui.pageManager', function() {
       var topmostPage = null;
       for (var name in this.registeredOverlayPages) {
         var page = this.registeredOverlayPages[name];
-        if (page.visible &&
-            (!topmostPage || page.alwaysOnTop ||
-             this.getNestingLevel(page) > this.getNestingLevel(topmostPage))) {
+        if (!page.visible)
+          continue;
+
+        if (page.alwaysOnTop)
+          return page;
+
+        if (!topmostPage ||
+             this.getNestingLevel(page) > this.getNestingLevel(topmostPage)) {
           topmostPage = page;
         }
       }