Timeline: simplify handling of event category colors

third_party/WebKit/Source/devtools/front_end/timeline/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 197 matching lines @@
     text-align: right;
 }
 
 .timeline-aggregated-legend-swatch {
     display: inline-block;
     width: 11px;
     height: 11px;
     margin: 0 6px;
     position: relative;
     top: 1px;
-    border: 1px solid;
+    border: 1px solid rgba(0, 0, 0, 0.2);
 }
 
 .popover ul {
     margin: 0;
     padding: 0;
     list-style-type: none;
 }
 
 #resources-container-content {
     overflow: hidden;
@@ skipping 142 matching lines @@
 .timeline-details-chip-title {
     font-size: 13px;
     padding: 8px;
     display: flex;
     align-items: center;
 }
 
 .timeline-details-chip-title > div {
     width: 12px;
     height: 12px;
+    border: 1px solid rgba(0, 0, 0, 0.2);
     display: inline-block;
     margin-right: 4px;
     content: " ";
 }
 
 .timeline-details-view-row-title {
     color: rgb(152, 152, 152);
     overflow: hidden;
 }
 
@@ skipping 338 matching lines @@
     border-bottom: 1px solid #ddd;
     background-color: #f3f3f3
 }
 
 .timeline-stack-view-header {
     height: 26px;
     background-color: white;
     padding: 6px 10px;
     color: #5a5a5a;
 }