DevTools: update buttons to new style

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

 /*
  * Copyright 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.
  */
 
 .list {
     flex: auto 0 1;
     overflow-y: auto;
     border: 1px solid rgb(231, 231, 231);
@@ skipping 65 matching lines @@
 
 .editor-buttons {
     flex: none;
     display: flex;
     flex-direction: row;
     align-items: center;
     justify-content: flex-start;
     padding: 5px;
 }
 
-.material .editor-buttons {
-    padding: 5px 9px 9px 9px;
-}
-
 .editor-buttons > button {
     flex: none;
     margin-right: 10px;
 }
 
 .editor-content input {
     margin-right: 10px;
 }
 
 .editor-content input.error-input {
     background-color: white;
 }