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

printing/printing_context_mac.mm

Index: printing/printing_context_mac.mm
diff --git a/printing/printing_context_mac.mm b/printing/printing_context_mac.mm
index f839802bd3ea7f7993aedad19aab022c7395ae35..8a27e1b3da98caa602dbcfeefa09259bdeff2563 100644
--- a/printing/printing_context_mac.mm
+++ b/printing/printing_context_mac.mm
@@ -111,14 +111,17 @@ PrintingContext::Result PrintingContextMac::UpdatePrinterSettings(
   bool landscape;
   bool print_to_pdf;
   int copies;
-  int duplex_mode;
+  DictionaryValue* duplex_info;
+  int user_selected_duplex_value;
   std::string device_name;
 
   if (!job_settings.GetBoolean(kSettingLandscape, &landscape) ||
       !job_settings.GetBoolean(kSettingCollate, &collate) ||
       !job_settings.GetBoolean(kSettingColor, &color) ||
       !job_settings.GetBoolean(kSettingPrintToPDF, &print_to_pdf) ||
-      !job_settings.GetInteger(kSettingDuplexMode, &duplex_mode) ||
+      !job_settings.GetDictionary(kSettingDuplexModeInfo, &duplex_info) ||
+      !duplex_info->GetInteger(kUserSelectedDuplexValue,
+                               &user_selected_duplex_value) ||
       !job_settings.GetInteger(kSettingCopies, &copies) ||
       !job_settings.GetString(kSettingDeviceName, &device_name)) {
     return OnError();
@@ -137,7 +140,7 @@ PrintingContext::Result PrintingContextMac::UpdatePrinterSettings(
       return OnError();
 
     if (!SetDuplexModeInPrintSettings(
-            static_cast<DuplexMode>(duplex_mode))) {
+            static_cast<DuplexMode>(user_selected_duplex_value))) {
       return OnError();
     }