perf hists browser: Warn about lost events

Just like the old perf top --tui and the --stdio version.

But because we have the initial menu to choose which event to show in a
session with multiple events we can see how many chunks were lost in
each of the event types, clarifying which events are being affected the
most.

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-47yyqbubmjzch2chezmb21m6@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/util/ui/browser.c b/tools/perf/util/ui/browser.c
index d2051be..5568291 100644
--- a/tools/perf/util/ui/browser.c
+++ b/tools/perf/util/ui/browser.c
@@ -176,16 +176,29 @@
 	ui_browser__refresh(browser);
 }
 
-int ui_browser__warning(struct ui_browser *browser, const char *format, ...)
+int ui_browser__warning(struct ui_browser *browser, int timeout,
+			const char *format, ...)
 {
 	va_list args;
-	int key;
+	char *text;
+	int key = 0, err;
 
 	va_start(args, format);
-	while ((key = __ui__warning("Warning!", format, args)) == K_RESIZE)
-		ui_browser__handle_resize(browser);
+	err = vasprintf(&text, format, args);
 	va_end(args);
 
+	if (err < 0) {
+		va_start(args, format);
+		ui_helpline__vpush(format, args);
+		va_end(args);
+	} else {
+		while ((key == ui__question_window("Warning!", text,
+						   "Press any key...",
+						   timeout)) == K_RESIZE)
+			ui_browser__handle_resize(browser);
+		free(text);
+	}
+
 	return key;
 }