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

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 3c48e45e271cd50787056e8a05a498e00e9954e9..899673a4382267d012f50a733fa70baf30f2b707 100644
--- a/chrome/browser/resources/print_preview/copies_settings.js
+++ b/chrome/browser/resources/print_preview/copies_settings.js
@@ -22,6 +22,15 @@ cr.define('print_preview', function() {
     this.collateCheckbox_ = $('collate');
     this.hint_ = $('copies-hint');
     this.twoSidedCheckbox_ = $('two-sided');
+
+    // Constant values matches printing::DuplexMode enum. Not using const
+    // keyword because it is not allowed by JS strict mode.
+    this.SIMPLEX = 0;
+    this.LONG_EDGE = 1;
+    this.SHORT_EDGE = 2;
+    this.UNKNOWN = -1;
+    // Store the default duplex setting value which we got from the printer.
+    this.printerDefaultDuplexValue_ = this.UNKNOWN;
   }
 
   cr.addSingletonGetter(CopiesSettings);
@@ -56,15 +65,19 @@ cr.define('print_preview', function() {
     },
 
     /**
-     * Gets the duplex mode for printing.
+     * Gets the duplex mode information 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;
+    get duplexMode() {
+      // On Windows, some printer doesn't specify their duplex values in the
+      // printer schema. If the printer duplex value is UNKNOWN, it is better
+      // to assign either "0" or "1" in DEVMODE structure according to user
+      // selected duplex value.
+      // Ref bug: http://code.google.com/p/chromium/issues/detail?id=89204

[vandebo (ex-Chrome), 2011/09/03 00:58:26]

http://crbug.com/89204

[kmadhusu, 2011/09/03 02:44:53]

Done.

+      return !this.twoSidedCheckbox_.checked ?

[vandebo (ex-Chrome), 2011/09/03 00:58:27]

Double trinary is pretty ugly... how about if, else if, else

[kmadhusu, 2011/09/03 02:44:53]

Done.

+             this.SIMPLEX :
+             (this.printerDefaultDuplexValue == this.UNKNOWN ?
+                 this.SHORT_EDGE : this.LONG_EDGE);

[vandebo (ex-Chrome), 2011/09/03 00:58:27]

I wonder if it would be clearer to define this.DUPLEX = 1, and use that here.

[kmadhusu, 2011/09/03 02:44:53]

Yeah it will be consistent with the comment. Done.

     },
 
     /**
@@ -158,7 +171,10 @@ cr.define('print_preview', function() {
         fadeInElement(this.copiesOption_);
         $('hr-before-copies').classList.add('invisible');
       }
-      this.twoSidedCheckbox_.checked = e.printerCapabilities.setDuplexAsDefault;
+      this.printerDefaultDuplexValue =
+          e.printerCapabilities.printerDefaultDuplexValue;
+      if (this.printerDefaultDuplexValue >= 0)

[vandebo (ex-Chrome), 2011/09/03 00:58:27]

!= UNKNOWN ?

[kmadhusu, 2011/09/03 02:44:53]

Done.

+        this.twoSidedCheckbox_.checked = this.printerDefaultDuplexValue;
     },
 
     /**