Fix Password Manager Performance Issues

chrome/browser/resources/options/password_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. */
 
 #password-manager > div.content-area {
   width: 600px;
 }
 
 #password-search-column {
   bottom: 10px;
   position: absolute;
   right: 0;
 }
 
 html[dir=rtl] #password-search-column {
   left: 0;
   right: auto;
 }
 
 #password-list-headers {
   position: relative;
   width: 100%;
 }
 
 #passwords-title {
   display: inline-block;
 }
+
+#saved-passwords-list {
+  max-height: 192px;
+}
+
+#password-exceptions-list {
+  max-height: 192px;
+}

[Dan Beam, 2016/10/25 00:50:17]

nit: combine rules and add a comment

#saved-passwords-list,
#password-exceptions-list {
  max-height: 192px;  /* For performance (crbug.com/651049). */
}