Disable HTML close button in Reader Mode

components/dom_distiller/core/css/distilledpage.css

 /* Copyright 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. */
 
 /* Set the global 'box-sizing' state to 'border-box'.
  * *::after and *::before used to select pseudo-elements not selectable by *. */
 
 *,
 *::after,
 *::before {
@@ skipping 238 matching lines @@
   border-top: 1px solid #555;
   color: #3adaff;
 }
 
 .sepia #closeReaderView {
   border-top: 1px solid rgb(147, 125, 102);
   color: #55F;
 }
 
 #closeReaderView {
+  /*
+  TODO(mdjones): Remove the "display: none;" style when the Reader Mode bar
+                 behaves like the toolbar when scrolling.
+  */
+  display: none;
   flex: 0 0 auto;
   font-family: 'Roboto', sans-serif;
   font-weight: 700;
   line-height: 14px;
   padding: 24px 16px;
   font-size: 14px;
   text-align: right;
   text-decoration: none;
   text-transform: uppercase;
   width: 100%;
@@ skipping 214 matching lines @@
 }
 
 .youtubeIframe {
   height: 100%;
   left: 0px;
   position: absolute;
   top: 0px;
   width: 100%;
 }