PrintPreview: Added code to identify the printer default duplex value.

chrome/browser/resources/print_preview/copies_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 CopiesSettings object.
    * @constructor
    */
   function CopiesSettings() {
     this.copiesOption_ = $('copies-option');
     this.textfield_ = $('copies');
     this.incrementButton_ = $('increment');
     this.decrementButton_ = $('decrement');
     // Minimum allowed value for number of copies.
     this.minValue_ = 1;
     // Maximum allowed value for number of copies.
     this.maxValue_ = 999;
     this.collateOption_ = $('collate-option');
     this.collateCheckbox_ = $('collate');
     this.hint_ = $('copies-hint');
     this.twoSidedCheckbox_ = $('two-sided');
+    // Store the default duplex setting value which we got from the printer.
+    this.printerDefaultDuplexValue = -1;

[dpapad, 2011/09/02 03:01:07]

Rename member var to printerDefaultDuplexValue_.

[kmadhusu, 2011/09/03 00:34:00]

Done.

   }
 
   cr.addSingletonGetter(CopiesSettings);
 
   CopiesSettings.prototype = {
     /**
      * The number of copies represented by the contents of |this.textfield_|.
      * If the text is not valid returns |this.minValue_|.
      * @type {number}
      */
@@ skipping 14 matching lines @@
 
     /**
      * Getter method for |twoSidedCheckbox_|.
      * @type {HTMLInputElement}
      */
     get twoSidedCheckbox() {
       return this.twoSidedCheckbox_;
     },
 
     /**
-     * Gets the duplex mode for printing.
-     * @return {number} duplex mode.
+     * Gets the duplex mode information for printing.
+     * @return {object} duplex mode object specifies the printer specified

[dpapad, 2011/09/02 03:01:07]

Nit: s/{object}/{Object}
Nit (optional): Change @return comment to "A custom object holding the printer
default value and user selected duplex mode value."

[kmadhusu, 2011/09/03 00:34:00]

Reverted the code to return a number. 

+     * default value and user selected duplex mode value.
      */
-     get duplexMode() {
+     get duplexModeInfo() {
       // Constant values matches printing::DuplexMode enum. Not using const
       // keyword because it is not allowed by JS strict mode.
       var SIMPLEX = 0;

[dpapad, 2011/09/02 03:01:07]

You can define these constants as regular member vars instead of local, this is
what we do with other constants for example |this.maxValue_| and
|this.minValue_|.
Maybe at some point we should rename to this,MAX_VALUE etc to make it more clear
that they are supposed to be constant.

[kmadhusu, 2011/09/03 00:34:00]

Done.

       var LONG_EDGE = 1;
-      return !this.twoSidedCheckbox_.checked ? SIMPLEX : LONG_EDGE;
+      return {'printerDefaultDuplexValue': this.printerDefaultDuplexValue,
+              'userSelectedDuplexValue': !this.twoSidedCheckbox_.checked ?
+                                         SIMPLEX : LONG_EDGE};
     },
 
     /**
      * @return {boolean} true if |this.textfield_| is empty, or represents a
      *     positive integer value.
      */
     isValid: function() {
       return !this.textfield_.value || isPositiveInteger(this.textfield_.value);
     },
 
@@ skipping 73 matching lines @@
      * @private
      */
     onPrinterCapabilitiesUpdated_: function(e) {
       if (e.printerCapabilities.disableCopiesOption) {
         fadeOutElement(this.copiesOption_);
         $('hr-before-copies').classList.remove('invisible');
       } else {
         fadeInElement(this.copiesOption_);
         $('hr-before-copies').classList.add('invisible');
       }
-      this.twoSidedCheckbox_.checked = e.printerCapabilities.setDuplexAsDefault;
+      this.printerDefaultDuplexValue =
+          e.printerCapabilities.printerDefaultDuplexValue;
+      if (this.printerDefaultDuplexValue >= 0)

[dpapad, 2011/09/02 03:01:07]

I think this if statement is equivalent to
this.twoSidedCheckbox_.checked = !!this.printerDefaultDuplexValue;

[kmadhusu, 2011/09/03 00:34:00]

No. this.printerDefaultDuplexValue is not a boolean. It is a tri-state variable
(UNKNOWN = -1, SIMPLEX = 0, DUPLEX = 1)

+        this.twoSidedCheckbox_.checked = this.printerDefaultDuplexValue;
     },
 
     /**
      * Listener triggered when |incrementButton_| is clicked.
      * @private
      */
     onIncrementButtonClicked_: function() {
       this.onButtonClicked_(1);
     },
 
@@ skipping 36 matching lines @@
         fadeOutElement(this.hint_);
       }
       this.hint_.setAttribute('aria-hidden', this.isValid());
     }
   };
 
   return {
     CopiesSettings: CopiesSettings,
   };
 });