PrintPreview:[MAC] Added "Open PDF In Preview" option to open the pdf in native preview app.

printing/print_job_constants.cc

Index: printing/print_job_constants.cc
diff --git a/printing/print_job_constants.cc b/printing/print_job_constants.cc
index adebd1406c53b12a92251dae25f1078e2c603863..c671326aa244e434045894d0f4fa24e2f3665664 100644
--- a/printing/print_job_constants.cc
+++ b/printing/print_job_constants.cc
@@ -123,6 +123,10 @@ const char kSettingPrintToPDF[] = "printToPDF";
 const int FIRST_PAGE_INDEX = 0;
 const int COMPLETE_PREVIEW_DOCUMENT_INDEX = -1;
 
+#if defined(OS_MACOSX)
+const char kSettingOpenPDFInPreview[] = "OpenPDFInPreview";
+#endif
+
 #if defined (USE_CUPS)
 const char kBlack[] = "Black";
 const char kCMYK[] = "CMYK";