DevTools: fix overlapping toolbars in Sources and SearchableViews

third_party/WebKit/Source/devtools/front_end/sources/sourcesView.css

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 21 matching lines @@
     flex: auto;
     position: relative;
 }
 
 #sources-panel-sources-view .sources-toolbar {
     display: flex;
     flex: 0 0 27px;
     background-color: #f3f3f3;
     border-top: 1px solid #dadada;
     overflow: hidden;
+    z-index: 0;
 }
 
 .sources-toolbar .toolbar {
     cursor: default;
 }
 
 .sources-toolbar-spacer {
     flex: auto;
     pointer-events: none;
 }
@@ skipping 112 matching lines @@
     90% { background-color: rgba(158, 54, 153, 0); }
     to { background-color: transparent; }
 }
 
 @keyframes source-line-modification-foreground-fadeout {
     from { color: white; }
     50% { color: white; }
     90% { color: intial; }
     to { color: intial; }
 }