Enlarge clickable area of the Files.app's butter bar's close action (x).

chrome/browser/resources/file_manager/css/file_manager.css

 /* 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. */
 
 html {
   height: 100%;
 }
 
 html.col-resize * {
   cursor: col-resize !important;
@@ skipping 72 matching lines @@
   display: -webkit-box;
   min-height: 35px;
 }
 
 #butter-bar .actions {
   -webkit-box-align: center;
   -webkit-box-orient: horizontal;
   -webkit-box-pack: end;
   -webkit-margin-start: 6px;
   display: -webkit-box;
-  height: 20px;
 }
 
 #butter-bar .actions a {
   color: rgb(17, 85, 204);
   cursor: pointer;
+  vertical-align: middle;
 }
 
 #butter-bar .actions a.x {
   background: center center no-repeat;
   background-image: -webkit-image-set(
     url('../images/files/ui/close_bar.png') 1x,
     url('../images/files/ui/2x/close_bar.png') 2x);
   display: inline-block;
-  height: 12px;
-  padding: 4px 2px;
-  width: 12px;
+  height: 35px;  /* #butter-bar .content's min-height. */
+  margin-right: -12px;
+  width: 35px;
 }
 
-#butter-bar .actions a:first-child {
-  margin-left: 2px;
-}
-
-#butter-bar .actions a:last-child {
-  margin-right: -2px;  /* Overlap the padding with butter-bar padding. */
+#butter-bar .actions a.x:first-child {
+  margin-left: -6px;
 }
 
 #butter-bar.error {
   background-color: rgba(221, 75, 57, 0.2);
 }
 
 #butter-bar .butter-message.single-line {
   overflow: hidden;
   text-overflow: ellipsis;
   white-space: nowrap;
@@ skipping 1496 matching lines @@
 
 #default-action-dialog {
   min-width: 300px;
   width: auto;
 }
 
 .drive-welcome-wrapper {
   /* drive_welcome.css will override it once loaded. */
   display: none;
 }