Fix closure compililation error in Files.app.

ui/file_manager/file_manager/foreground/js/toolbar_controller.js

Index: ui/file_manager/file_manager/foreground/js/toolbar_controller.js
diff --git a/ui/file_manager/file_manager/foreground/js/toolbar_controller.js b/ui/file_manager/file_manager/foreground/js/toolbar_controller.js
index 7f0b3c8ddc809a8ae01472d3be261261cfab9ebe..2c8a47189561e2c1ab4dd8aeb093044ca3701fc4 100644
--- a/ui/file_manager/file_manager/foreground/js/toolbar_controller.js
+++ b/ui/file_manager/file_manager/foreground/js/toolbar_controller.js
@@ -95,6 +95,7 @@ ToolbarController.prototype.onCancelSelectionButtonClicked_ = function() {
  */
 ToolbarController.prototype.onNavigationListRelayout_ = function() {
   // Make the width of spacer same as the width of navigation list.
-  var navWidth = parseFloat(getComputedStyle(this.navigationList_).width);
+  var navWidth = parseFloat(
+      window.getComputedStyle(this.navigationList_).width);
   this.cancelSelectionButtonWrapper_.style.width = navWidth + 'px';
 }