DevTools: perfectly center shevron icon

third_party/WebKit/Source/devtools/front_end/ui/tabbedPane.css

 /*
  * Copyright (C) 2006, 2007, 2008 Apple Inc.  All rights reserved.
  * Copyright (C) 2009 Anthony Ricaud <rik@webkit.org>
  * Copyright (C) 2011 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:
  *
  * 1. Redistributions of source code must retain the above copyright
@@ skipping 121 matching lines @@
     visibility: hidden;
 }
 
 .tabbed-pane-header-tab:hover .tabbed-pane-close-button,
 .tabbed-pane-header-tab.selected .tabbed-pane-close-button {
     visibility: visible;
 }
 
 .tabbed-pane-header-tabs-drop-down-container {
     float: left;
-    position: relative;
-    vertical-align: bottom;
-    line-height: 24px;
     opacity: 0.8;
-    color: inherit;
-    font-size: 133%;
     cursor: pointer;
+    display: flex;
+    align-items: center;
+    height: 100%;
 }
 
 .tabbed-pane-header-tabs-drop-down-container > .chevron-icon {
     background-color: hsla(0,0%,20%,1);
     display: block;
 }
 
 .tabbed-pane-header-tabs-drop-down-container:hover {
     background-color: rgb(229, 229, 229);
 }
@@ skipping 110 matching lines @@
 
 .tabbed-pane-left-toolbar {
     margin-right: -4px;
     flex: none;
 }
 
 .tabbed-pane-right-toolbar {
     margin-left: -4px;
     flex: none;
 }