NetServices: Add debugging constants and messages

These allow for additional messages about the progress/status of the request.
For now, the messages are sent unconditionally, though it may be reasonable to
in the future switch to sending them only when enabled.

Change-Id: Ic45a0055037af02c689494fa5ce0acd03592ad7e

headers/private/netservices2/NetServicesDefs.h

@@ -105,6 +105,12 @@ namespace UrlEventData {
 	extern const char* Success;
 	extern const char* DebugType;
 	extern const char* DebugMessage;
+
+	enum {
+		DebugInfo = '_DBI',
+		DebugWarning = '_DBW',
+		DebugError = '_DBE'
+	};
 }
 
 }