[Print Preview]: Added code to support pdf fit to page functionality.

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 c5f010576a376800d6cc05b5df668f232c69aff4..5448d26e97485b2751f605125e0882e5987f52fc 100644
--- a/printing/print_job_constants.cc
+++ b/printing/print_job_constants.cc
@@ -42,6 +42,10 @@ const char kSettingDeviceName[] = "deviceName";
 // Print job duplex mode.
 const char kSettingDuplexMode[] = "duplex";
 
+// Option to fit source page contents to printer paper size: true if
+// selected else false.
+const char kSettingFitToPageEnabled[] = "fitToPageEnabled";
+
 // True, when a new set of draft preview data is required.
 const char kSettingGenerateDraftData[] = "generateDraftData";