Added Chrome profile option in registry.

cloud_print/virtual_driver/virtual_driver_switches.h

Index: cloud_print/virtual_driver/virtual_driver_switches.h
diff --git a/cloud_print/virtual_driver/virtual_driver_switches.h b/cloud_print/virtual_driver/virtual_driver_switches.h
index 54db54cf348eb6e1e32830216764663923ca6664..1c708092a2c1267f3f5204870f3d1af407d5463d 100644
--- a/cloud_print/virtual_driver/virtual_driver_switches.h
+++ b/cloud_print/virtual_driver/virtual_driver_switches.h
@@ -12,6 +12,9 @@ namespace switches {
 // TODO(abodenha@chromium.org) Reunify them in some sensible manner.
 // Bug: www.crbug.com/88991
 
+// Location of Chrome user profile. Optional.
+extern const char kCloudPrintUserDataDir[];
+
 // Used with kCloudPrintFile.  Tells Chrome to delete the file when
 // finished displaying the print dialog.
 extern const char kCloudPrintDeleteFile[];