Print Preview: Refactoring layout mode related logic to LayoutSettings class.

chrome/browser/resources/print_preview/copies_settings.js

Index: chrome/browser/resources/print_preview/copies_settings.js
diff --git a/chrome/browser/resources/print_preview/copies_settings.js b/chrome/browser/resources/print_preview/copies_settings.js
index 72893b6cad693fca74e50f0093a8ec9a0349e48e..df18c487bc952d9ba530b74a4ee8645b6ea9ec16 100644
--- a/chrome/browser/resources/print_preview/copies_settings.js
+++ b/chrome/browser/resources/print_preview/copies_settings.js
@@ -54,6 +54,18 @@ cr.define('print_preview', function() {
     },
 
     /**
+     * Gets the duplex mode for printing.
+     * @return {number} duplex mode.
+     */
+     get duplexMode() {
+      // Constant values matches printing::DuplexMode enum. Not using const
+      // keyword because it is not allowed by JS strict mode.
+      var SIMPLEX = 0;
+      var LONG_EDGE = 1;
+      return !this.twoSidedCheckbox_.checked ? SIMPLEX : LONG_EDGE;
+    },
+
+    /**
      * @return {boolean} true if |this.textfield_| is empty, or represents a
      *     positive integer value.
      */