DevTools: traverse widget hierarchy to reveal views.

third_party/WebKit/Source/devtools/front_end/audits/auditResultTree.css

 /*
  * Copyright 2015 The Chromium Authors. All rights reserved.
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 .severity {
     background-image: url(Images/toolbarButtonGlyphs.png);
     background-size: 352px 168px;
     display: inline-block;
-    width: 10px;
-    height: 10px;
+    width: 11px;
+    height: 11px;
     position: relative;
     top: 1px;
     margin-right: 4px;
 }
 
 li {
     -webkit-user-select: text;
 }
 
 @media (-webkit-min-device-pixel-ratio: 1.5) {
 .severity {
     background-image: url(Images/toolbarButtonGlyphs_2x.png);
 }
 } /* media */
 
 .severity.severe {
     background-position: -224px -96px;
 }
 
 .severity.warning {
     background-position: -246px -96px;
 }
 
 .severity.info {
     background-position: -235px -96px;
 }
 .audit-result {
     font-weight: bold;
 }