Devtools: Add new row in toolbarButtonGlyphs and layout editor icon

Source/devtools/front_end/components/breakpointsList.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 106 matching lines @@
     cursor: default;
 }
 
 .event-listener-breakpoints li.parent {
     margin-left: 1px;
 }
 
 .event-listener-breakpoints li.parent::before {
     -webkit-user-select: none;
     background-image: url(Images/toolbarButtonGlyphs.png);
-    background-size: 352px 144px;
+    background-size: 352px 168px;
     opacity: 0.5;
     content: "a";
     width: 8px;
     float: left;
     margin: 2px 2px 0 -2px;
     color: transparent;
     text-shadow: none;
 }
 
 @media (-webkit-min-device-pixel-ratio: 1.5) {
@@ skipping 24 matching lines @@
 }
 
 .dom-breakpoints-list > li {
     display: flex;
 }
 
 .dom-breakpoints-list .dom-breakpoint > div {
     overflow: hidden;
     text-overflow: ellipsis;
 }