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

printing/printing_context_win.cc

 // 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.
 
 #include "printing/printing_context_win.h"
 
 #include <winspool.h>
 
 #include <algorithm>
 
@@ skipping 365 matching lines @@
   dev_mode->dmCopies = std::max(copies, 1);
   if (dev_mode->dmCopies > 1)  // do not change collate unless multiple copies
     dev_mode->dmCollate = collate ? DMCOLLATE_TRUE : DMCOLLATE_FALSE;
   switch (duplex_mode) {
     case LONG_EDGE:
       dev_mode->dmDuplex = DMDUP_VERTICAL;
       break;
     case SHORT_EDGE:
       dev_mode->dmDuplex = DMDUP_HORIZONTAL;
       break;
-    default:  // simplex
+    case SIMPLEX:
       dev_mode->dmDuplex = DMDUP_SIMPLEX;
       break;
+    default:  // UNKNOWN_DUPLEX_MODE
+      break;
   }
   dev_mode->dmOrientation = landscape ? DMORIENT_LANDSCAPE : DMORIENT_PORTRAIT;
 
   // Update data using DocumentProperties.
   if (DocumentProperties(NULL, printer, device_name_wide, dev_mode, dev_mode,
                          DM_IN_BUFFER | DM_OUT_BUFFER) != IDOK) {
     ClosePrinter(printer);
     return OnError();
   }
 
@@ skipping 364 matching lines @@
   if (buf_size) {
     buffer->reset(new uint8[buf_size]);
     memset(buffer->get(), 0, buf_size);
     if (!GetPrinter(printer, level, buffer->get(), buf_size, &buf_size)) {
       buffer->reset();
     }
   }
 }
 
 }  // namespace printing