Make hitting "Enter" submit the add/change profile dialog.

chrome/browser/resources/options/manage_profile_overlay.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. */
 
 #manage-profile-overlay {
   width: 512px;
 }
 
 .profile-icon-grid-item {
   height: 31px;
@@ skipping 46 matching lines @@
   max-height: 0;
   padding: 0 10px;
 }
 
 #create-profile-icon-grid,
 #manage-profile-icon-grid {
   background-color: rgba(255, 255, 255, 0.75);
   padding: 2px;
 }
 
+#create-profile-ok,
+#manage-profile-ok {
+  border-color: rgba(0, 0, 0, 0.5);
+}
+
 /* Adds a grey horizontal line below content area.  */
 #create-profile-content::after,
 #manage-profile-content::after {
   background: #c0c0c0;
   content: '';
   display: block;
   height: 1px;
   margin-top: 25px;
   width: 100%;
 }
@@ skipping 23 matching lines @@
 }
 
 #delete-profile-message {
   -webkit-padding-start: 48px;
   background-repeat: no-repeat;
 }
 
 html[dir='rtl'] #delete-profile-message {
   background-position: right;