Removing 3D effect for bluetooth keyboard pairing buttons.

chrome/browser/resources/options/chromeos/bluetooth.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. */
 
 .bluetooth-device-list {
   margin: 10px 0;
   padding: 5px 10px;
 }
 
 .bluetooth-device[notconnectable] {
@@ skipping 92 matching lines @@
 #bluetooth-pairing-passkey-entry,
 #bluetooth-pairing-pincode-entry {
   margin: 40px 0;
 }
 
 .bluetooth-keyboard-button {
   -webkit-padding-end: 15px;
   -webkit-padding-start: 15px;
   border: 1px solid #ccc;
   border-radius: 4px;
-  box-shadow: 0 0 0 1px #222,
-              inset 0 1px 1px 1px #fff,
-              inset 0 -1px 1px 1px #eee;
+  box-shadow: 0 0 0 1px #222;
   color: #222;
   display: inline-block;
   font-size: 16px;
   height: 38px;
   line-height: 38px;
   margin: 0 10px 0 0;
   position: relative;
   text-align: center;
   text-shadow: 0 1px 0 rgba(255, 255, 255, 0.5);
   vertical-align: baseline;
@@ skipping 26 matching lines @@
 .bluetooth-keyboard-button.key-next {
   background: rgb(77, 144, 254);
   background-image: none;
   border: 2px solid rgb(77, 144, 254);
   box-shadow: none;
   color: #fff;
 }
 
 .bluetooth-keyboard-button.key-untyped {
   border: 1px solid #d4d4d4;
-  box-shadow: 0 0 0 1px #888,
-              inset 0 1px 1px 1px #fff,
-              inset 0 -1px 1px 1px #eee;
+  box-shadow: 0 0 0 1px #888;
   color: #666;
 }