Fix some lingering WebUI focus issues.

chrome/browser/resources/extensions/extensions.js

Index: chrome/browser/resources/extensions/extensions.js
diff --git a/chrome/browser/resources/extensions/extensions.js b/chrome/browser/resources/extensions/extensions.js
index 3dc9635ade7674f3a669872e8ec044e4ddb3576b..405a460ed4f648e255d235bbe389f6dba58d9458 100644
--- a/chrome/browser/resources/extensions/extensions.js
+++ b/chrome/browser/resources/extensions/extensions.js
@@ -386,9 +386,16 @@ cr.define('extensions', function() {
     }
 
     if (node) {
-      var lastFocused = document.activeElement;
+      var lastFocused;
+
+      var focusOutlineManager = cr.ui.FocusOutlineManager.forDocument(document);
+      if (focusOutlineManager.visible)
+        lastFocused = document.activeElement;
+
       $('overlay').addEventListener('cancelOverlay', function f() {
-        lastFocused.focus();
+        if (lastFocused && focusOutlineManager.visible)
+          lastFocused.focus();
+
         $('overlay').removeEventListener('cancelOverlay', f);
       });
       node.classList.add('showing');