Change print setting conventions for margins to support more options.

chrome/browser/resources/print_preview/margin_settings.js

 // Copyright (c) 2011 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.
 
 cr.define('print_preview', function() {
   'use strict';
 
   /**
    * Creates a Margins object that holds four margin values. The units in which
    * the values are expressed can be any numeric value.
@@ skipping 161 matching lines @@
 
     /**
      * @return {number} The value of the selected margin option.
      * @private
      */
     get selectedMarginsValue_() {
       return this.marginList_.options[this.marginList_.selectedIndex].value;
     },
 
     /**
+     * Gets the string representation of the margin type selected.
+     *
+     * @return {string}
+     */
+    get selectedMarginsAsString() {
+      if (this.isNoMarginsSelected())
+        return "noMargins";
+      else if (this.isCustomMarginsSelected())
+        return "customMargins";
+      else
+        return "defaultMargins";
+    },
+
+    /**
      * @return {boolean} True if default margins are selected.
      */
     isDefaultMarginsSelected: function() {
       return this.selectedMarginsValue_ == MarginSettings.MARGINS_VALUE_DEFAULT;
     },
 
     /**
      * @return {boolean} True if no margins are selected.
      */
     isNoMarginsSelected: function() {
@@ skipping 274 matching lines @@
       if (!previewModifiable)
         fadeOutElement(this.marginsOption_);
     }
   };
 
   return {
     MarginSettings: MarginSettings,
     PageLayout: PageLayout,
   };
 });