MD Downloads: change a lowercased, no-ink button to an <a>

chrome/browser/resources/md_downloads/item.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. */
 
 :host {
   display: flex;
   flex-direction: column;
   margin: 12px 0;
 }
 
@@ skipping 121 matching lines @@
   color: rgb(239, 108, 0);
 }
 
 #progress {
   --paper-progress-active-color: rgb(54, 126, 237);
   --paper-progress-container-color: rgb(223, 222, 223);
   width: auto;
 }
 
 .controls {
-  -webkit-margin-start: -8px;
+  -webkit-margin-start: -.57em;
 }
 
 #cancel,
 #retry,
 .keep,
 .discard {
   color: #5a5a5a;
 }
 
+#show {
+  margin: .7em .57em;
+}
+
 #controlled-by {
   -webkit-margin-start: 8px;
 }
 
 #controlled-by,
 #controlled-by a {
   color: #5a5a5a;
 }
 
 .is-active #controlled-by {
@@ skipping 21 matching lines @@
   width: 16px;
 }
 
 #incognito {
   bottom: 20px;
   content: -webkit-image-set(url(1x/incognito_marker.png) 1x,
                              url(2x/incognito_marker.png) 2x);
   position: absolute;
   right: 10px;
 }