Devtools: Add new row in toolbarButtonGlyphs and layout editor icon

Source/devtools/front_end/sidebarPane.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 55 matching lines @@
     position: relative;
 }
 
 .sidebar-pane-title.expanded,
 .sidebar-pane-title:last-child {
     border-bottom: 1px solid #ddd;
 }
 
 .sidebar-pane-title::before {
     background-image: url(Images/toolbarButtonGlyphs.png);
-    background-size: 352px 144px;
+    background-size: 352px 168px;
     opacity: 0.5;
     float: left;
     width: 11px;
     height: 11px;
     margin-right: 2px;
     content: "a";
     color: transparent;
 }
 
 @media (-webkit-min-device-pixel-ratio: 1.5) {
@@ skipping 52 matching lines @@
     visibility: hidden;
 }
 
 .styles-section.matched-styles:not(.read-only):hover .sidebar-pane-button-new-rule {
     visibility: visible;
 }
 
 .sidebar-pane-button-new-rule:hover {
     background-position: -23px 0;
 }