perf session: Move the hist_entries rb tree to perf_session

As we'll need to sort multiple times for multiple perf sessions,
so that we can then do a diff.

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: <1260803439-16783-1-git-send-email-acme@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/tools/perf/util/session.h b/tools/perf/util/session.h
index 20b2c9c..759d960 100644
--- a/tools/perf/util/session.h
+++ b/tools/perf/util/session.h
@@ -16,10 +16,12 @@
 	struct map_groups	kmaps;
 	struct rb_root		threads;
 	struct thread		*last_match;
+	struct rb_root		hists;
 	int			fd;
 	int			cwdlen;
 	char			*cwd;
 	bool			use_modules;
+	bool			use_callchain;
 	char filename[0];
 };
 
@@ -35,7 +37,8 @@
 	event_op	process_read_event;
 	event_op	process_throttle_event;
 	event_op	process_unthrottle_event;
-	int		(*sample_type_check)(u64 sample_type);
+	int		(*sample_type_check)(u64 sample_type,
+					     struct perf_session *session);
 	unsigned long	total_unknown;
 	bool		full_paths;
 };