Mac: Update CSS appearance for input[type=color][list].

Source/core/css/themeMac.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.
  */
 
-select {
+select, input[type="color"][list] {
     background-color: #f8f8f8;
-    border-color: #a6a6a6;
+    border: 1px solid #a6a6a6;
 }
 
 select[size],
 select[multiple],
 select[size][multiple] {
     background: white;
     border: 1px inset gray;
 }