Add DisplayLayoutManagerMulti (WIP)

chrome/browser/resources/options/chromeos/display_options.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. */
 
 #display-options-page {
   background-color: rgb(240, 240, 240);
 }
 
 #display-options-content-area {
   padding: 0;
@@ skipping 75 matching lines @@
 
 .display-mirrored {
   border: solid 1px;
 }
 
 .displays-focused {
   border: solid 2px rgb(0, 138, 255);
   color: rgb(0, 138, 255);
 }
 
+.displays-parent-left {
+  border-left: solid 1px rgb(255, 138, 0);
+}
+
+.displays-parent-right {
+  border-right: solid 1px rgb(255, 138, 0);
+}
+
+.displays-parent-top {
+  border-top: solid 1px rgb(255, 138, 0);
+}
+
+.displays-parent-bottom {
+  border-bottom: solid 1px rgb(255, 138, 0);
+}
+
 #display-options-select-mirroring {
   margin-right: 5px;
 }
 
 .display-options-button {
   width: 140px;
 }
 
 .display-options-button2 {
   width: 120px;
 }