Devtools: Add new row in toolbarButtonGlyphs and layout editor icon

Source/devtools/front_end/timeline/timelinePanel.css

 /*
  * Copyright (C) 2006, 2007, 2008 Apple Inc.  All rights reserved.
  * Copyright (C) 2009 Anthony Ricaud <rik@webkit.org>
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
@@ skipping 122 matching lines @@
     left: 0;
     width: 3px;
     border-top: 1px solid rgb(163, 163, 163);
     border-bottom: 1px solid rgb(163, 163, 163);
 }
 
 .timeline-tree-item-expand-arrow {
     display: inline-block;
     -webkit-user-select: none;
     -webkit-mask-image: url(Images/toolbarButtonGlyphs.png);
-    -webkit-mask-size: 352px 144px;
+    -webkit-mask-size: 352px 168px;
     width: 10px;
     height: 10px;
     content: "";
     background-color: rgb(110, 110, 110);
     position: relative;
     top: -1px;
     left: -1px;
 }
 
 @media (-webkit-min-device-pixel-ratio: 1.5) {
 .timeline-tree-item-expand-arrow {
     -webkit-mask-image: url(Images/toolbarButtonGlyphs_2x.png);
 }
 } /* media */
 
 .timeline-tree-item-expand-arrow.parent {
     -webkit-mask-position: -4px -96px;
 }
 
 .timeline-tree-item-expand-arrow.parent.expanded {
     -webkit-mask-position: -20px -96px;
 }
 
 .timeline-expandable-arrow {
     background-image: url(Images/toolbarButtonGlyphs.png);
-    background-size: 352px 144px;
+    background-size: 352px 168px;
     opacity: 0.5;
     width: 10px;
     height: 10px;
     position: relative;
     top: 3px;
     left: 2px;
 }
 
 @media (-webkit-min-device-pixel-ratio: 1.5) {
 .timeline-expandable-arrow {
@@ skipping 29 matching lines @@
     display: inline-block;
 }
 
 .timeline-tree-item.background .timeline-tree-icon {
     background: none !important;
 }
 
 .timeline-tree-item-warning {
     display: block;
     background-image: url(Images/toolbarButtonGlyphs.png);
-    background-size: 352px 144px;
+    background-size: 352px 168px;
     width: 10px;
     height: 10px;
     float: right;
     background-position: -202px -107px;
     position: relative;
     top: 2px;
 }
 
 .timeline-tree-item-child-warning {
     opacity: 0.6;
@@ skipping 823 matching lines @@
     position: absolute;
     right: -2px;
     bottom: 0px;
     border-bottom: 1px solid hsl(0, 100%, 74%);
 }
 
 .timeline-tree-view .data-grid .selected .background-bar {
     background-color: rgba(255,255,255,0.25);
     border-bottom-color: transparent;
 }