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 MarginSettings object. This object encapsulates all settings and
    * logic related to the margins mode.
@@ skipping 43 matching lines @@
     /**
      * Gets the value of the selected margin option.
      * @private
      * @return {number}
      */
     get selectedMarginsValue_() {
       return this.marginList_.options[this.marginList_.selectedIndex].value;
     },
 
     /**
-     * Checks whether user has selected the Default Margins option or not.
+     * Gets the string representation of the margin type selected.
      *
-     * @return {boolean} true if default margins are selected.
+     * @return {string}
      */
-    isDefaultMarginsSelected: function() {
-      return this.selectedMarginsValue_ == this.defaultMarginsValue_;

[dpapad, 2011/10/12 15:59:05]

After landing http://codereview.chromium.org/7891016/, these changes are
conflicting. I would recommend adding method get marginTypeString without
removing isDefaultMarginsSelected, isNoMarginsSelected and
isCustomMarginsSelected.

[vandebo (ex-Chrome), 2011/10/12 17:32:49]

Agreed. Done.

+    get marginTypeString() {
+      if (this.selectedMarginsValue_ == this.noMarginsValue_)
+        return "noMargins";
+      else if (this.selectedMarginsValue_ == this.customMarginsValue_)
+        return "customMargins";
+      else
+        return "defaultMargins";
     },
 
     /**
      * Adds listeners to all margin related controls. The listeners take care
      * of altering their behavior depending on |hasPendingPreviewRequest|.
      */
     addEventListeners: function() {
       this.marginList_.onchange = this.onMarginsChanged_.bind(this);
       document.addEventListener('PDFLoaded', this.onPDFLoaded_.bind(this));
     },
@@ skipping 32 matching lines @@
     onPDFLoaded_: function() {
       if (!previewModifiable)
         fadeOutElement(this.marginsOption_);
     }
   };
 
   return {
     MarginSettings: MarginSettings,
   };
 });