[Devtools] Fixed dark theme scrollbars consistency in settings

third_party/WebKit/Source/devtools/front_end/settings/settingsScreen.css

 /*
  * Copyright (c) 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.
  */
 
 .help-window-main {
     color: rgb(48, 57, 66);
     background-color: white;
     padding: 11px 0 0 0;
@@ skipping 13 matching lines @@
     padding: 0 4px;
     flex: auto;
 }
 
 .help-footnote {
     border-top: 1px solid #EEEEEE;
     margin: 0;
     padding: 12px;
 }
 
-.help-window-main .help-container-wrapper::-webkit-scrollbar {
-    width: 11px;
-}
-
-.help-window-main .help-container-wrapper::-webkit-scrollbar-corner,
-.help-window-main .help-container-wrapper::-webkit-resizer {
-    display: none;
-}
-
-.help-window-main .help-container-wrapper::-webkit-scrollbar-thumb:vertical {
-    background: linear-gradient(to right, rgb(128, 128, 128), rgb(96, 96, 96) 40%, rgb(128, 128, 128));
-    border-radius: 5px;
-    min-height: 20px;
-}
-
-.help-window-main .help-container-wrapper::-webkit-scrollbar-thumb:vertical:hover,
-.help-window-main .help-container-wrapper::-webkit-scrollbar-thumb:vertical:active {
-    background: linear-gradient(to right, rgb(176, 176, 176), rgb(144, 144, 144) 40%, rgb(176, 176, 176));
-}
-
-.help-window-main .help-container-wrapper::-webkit-scrollbar-track:vertical {
-    background: linear-gradient(to right, rgb(10, 10, 10), rgb(32, 32, 32) 25%, rgb(32, 32, 32));
-    border-radius: 5px;
-}
-
 .help-container {
     width: 100%;
     -webkit-user-select: auto;
     -webkit-column-width: 288px;
 }
 
 .help-no-columns {
     -webkit-column-width: initial !important;
 }
 
@@ skipping 257 matching lines @@
     display: none;
 }
 
 .settings-experiment-hidden label {
     background-color: #ddd;
 }
 
 .settings-developer-mode .settings-experiment-hidden {
     display: block;
 }