perf hists: Don't free decayed entries if in the annotation browser

Just let it there till the user exits the annotation browser.

Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-nmaxuzreqhm5k10t2co5sk9a@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/ui/browsers/hists.c

@@ -976,9 +976,13 @@ do_annotate:
 			he = hist_browser__selected_entry(browser);
 			if (he == NULL)
 				continue;
-
+			/*
+			 * Don't let this be freed, say, by hists__decay_entry.
+			 */
+			he->used = true;
 			hist_entry__tui_annotate(he, evsel->idx, nr_events,
 						 timer, arg, delay_secs);
+			he->used = false;
 			ui_browser__update_nr_entries(&browser->b, browser->hists->nr_entries);
 		} else if (choice == browse_map)
 			map__browse(browser->selection->map);