perf session: Remove sample_type_check from event_ops

This is really something tools need to do before asking for the
events to be processed, leaving perf_session__process_events to
do just that, process events.

Also add a msg parameter to perf_session__has_traces() so that
the right message can be printed, fixing a regression added by
me in the previous cset (right timechart message) and also
fixing 'perf kmem', that was not asking if 'perf kmem record'
was ran.

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frédéric Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <1261957026-15580-6-git-send-email-acme@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c
index b0ba2ac..e94f346 100644
--- a/tools/perf/builtin-trace.c
+++ b/tools/perf/builtin-trace.c
@@ -106,7 +106,6 @@
 static struct perf_event_ops event_ops = {
 	.process_sample_event	= process_sample_event,
 	.process_comm_event	= event__process_comm,
-	.sample_type_check	= perf_session__has_traces,
 };
 
 static int __cmd_trace(struct perf_session *session)
@@ -580,6 +579,9 @@
 	if (session == NULL)
 		return -ENOMEM;
 
+	if (!perf_session__has_traces(session, "record -R"))
+		return -EINVAL;
+
 	if (generate_script_lang) {
 		struct stat perf_stat;