DevTools: migrate PropertiesWidget to shadow

third_party/WebKit/Source/devtools/front_end/elements/elementsPanel.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 41 matching lines @@
 }
 
 .style-panes-wrapper {
     overflow: auto;
 }
 
 .style-panes-wrapper > div:not(:first-child) {
     border-top: 1px solid #ccc;
 }
 
-.properties-widget-section {
-    padding: 2px 0px 2px 5px;
-    flex: none;
-}
-
 .elements-tree-header {
     height: 24px;
     border-top: 1px solid #eee;
     border-bottom: 1px solid #eee;
     display: flex;
     flex-direction: row;
     align-items: center;
 }
 
 .elements-tree-header-frame {
     margin-left: 6px;
     margin-right: 6px;
     flex: none;
 }