DevTools: draw realistic chrome on top of viewport in layers3dview

Source/devtools/front_end/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 728 matching lines @@
     background-color: rgba(255, 255, 255, 0.8);
     font-size: 30px;
     z-index: 500;
     display: flex;
     justify-content: center;
     align-items: center;
 }
 
 .layers-3d-view {
     overflow: hidden;
+    -webkit-user-select: none;
 }
 
 .layers-3d-view canvas {
     flex: 1 1;
 }
 
 .transform-control-panel .status-bar-item > .glyph {
     -webkit-mask-image: url(Images/transformControls.png);
     -webkit-mask-size: 96px 24px;
     opacity: 0.8;
@@ skipping 96 matching lines @@
 }
 
 .paint-profiler-image-view {
     overflow: hidden;
 }
 
 .paint-profiler-image-view img {
     border: solid 1px black;
     -webkit-transform-origin: 0px 0px;
 }