Devtools: Add new row in toolbarButtonGlyphs and layout editor icon

Source/devtools/front_end/ui/treeoutline.css

 /*
  * Copyright 2015 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.
  */
 
 .tree-outline {
     padding: 0 0 4px 4px;
     margin: 0;
     z-index: 0;
@@ skipping 67 matching lines @@
 }
 
 ol.tree-outline:focus li.selected * {
     color: inherit;
 }
 
 .tree-outline li::before {
     float: left;
     -webkit-user-select: none;
     -webkit-mask-image: url(Images/toolbarButtonGlyphs.png);
-    -webkit-mask-size: 352px 144px;
+    -webkit-mask-size: 352px 168px;
     content: "a";
     color: transparent;
     text-shadow: none;
     position: relative;
     margin-right: 1px;
     top: 1px;
     width: 10px;
     height: 10px;
 }
 
@@ skipping 16 matching lines @@
     -webkit-mask-position: -20px -96px;
 }
 
 .tree-outline ol.children {
     display: none;
 }
 
 .tree-outline ol.children.expanded {
     display: block;
 }