Remove "View Background Pages".

chrome/browser/resources/task_manager/task_manager.css

 /* Copyright (c) 2012 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. */
 
 html {
   overflow: hidden;
 }
 
 /* Outer frame of the dialog. */
 body {
@@ skipping 59 matching lines @@
 /* Bullets on the left of row. */
 .table-row > .table-row-cell:first-child::before {
   -webkit-border-radius: 3px;
   background: #ccc;
   content: '';
   display: block;
   margin: 7px 4px 7px 7px;
   width: 6px;
 }
 
-.table-background-row {
-  background-color: hsl(34, 91%, 87%);
-  background-image: -webkit-linear-gradient(rgba(255, 255, 255, 0.8),
-                                            rgba(255, 255, 255, 0));
-  border-color: hsl(34, 91%, 65%);
-}
-
 /* Cells in table. */
 .table-row-cell {
   -webkit-box-orient: horizontal;
   display: -webkit-box;
 }
 
 /* Containers of titles of tasks on the process. */
 .detail-container-title {
   -webkit-box-flex: 1;
   -webkit-box-orient: vertical;
@@ skipping 45 matching lines @@
 
 /* Container for the ok/cancel buttons. */
 .footer-right-container {
   -webkit-box-flex: 1;
   text-align: right;
 }
 
 button {
   margin: 2px 0 2px 8px;
 }