[DevTools] Fix left show/hide sidebar button icon.

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

 /*
  * Copyright (c) 2014 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.
  */
 
 :host {
     flex: none;
     padding: 0 2px;
 }
@@ skipping 472 matching lines @@
 
 .folder-toolbar-item.toolbar-glyph {
     -webkit-mask-position: -224px -144px;
 }
 
 .goto-source-toolbar-item.toolbar-glyph {
     -webkit-mask-position: 0 -120px;
 }
 
 .toolbar-state-left-show .sidebar-toolbar-item.toolbar-glyph {
-    -webkit-mask-position: -168px -76px;
+    -webkit-mask-position: -160px -72px;
 }
 
 .toolbar-state-left-hide .sidebar-toolbar-item.toolbar-glyph {
-    -webkit-mask-position: -199px -76px;
+    -webkit-mask-position: -192px -72px;
 }
 
 .toolbar-state-right-show .sidebar-toolbar-item.toolbar-glyph {
     -webkit-mask-position: -288px -72px;
 }
 
 .toolbar-state-right-hide .sidebar-toolbar-item.toolbar-glyph {
     -webkit-mask-position: -256px -72px;
 }
 
 .toolbar-state-on .record-toolbar-item.toolbar-glyph,
 .toolbar-state-active .filter-toolbar-item.toolbar-glyph,
 .toolbar-state-active .block-toolbar-item.toolbar-glyph {
     background-color: rgb(216, 0, 0) !important;
 }
 
 :host-context(.-theme-with-dark-background) .toolbar-state-active .filter-toolbar-item.toolbar-glyph,
 :host-context(.-theme-with-dark-background) .toolbar-state-active .block-toolbar-item.toolbar-glyph,
 :host-context(.-theme-with-dark-background) .toolbar-state-on .record-toolbar-item.toolbar-glyph {
     background-color: hsl(0, 100%, 65%) !important;
 }
 
 span.toolbar-select-container.toolbar-item.warning {
     background: #ffd7d7;
     padding: 0 5px 0 0;
     margin-right: 1px;
 }