perf hists browser: Indicate which callchain entries are annotated

Now that we can annotate entries in a callchain, show which ones have an
associated symbol and samples, by adding a right arrow just before the
symbol name when in verbose mode.

To toggle verbose mode press 'V'.

Cc: Adrian Hunter <[e-mail]>
Cc: Borislav Petkov <[e-mail]>
Cc: David Ahern <[e-mail]>
Cc: Don Zickus <[e-mail]>
Cc: Frederic Weisbecker <[e-mail]>
Cc: Jiri Olsa <[e-mail]>
Cc: Mike Galbraith <[e-mail]>
Cc: Namhyung Kim <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Cc: Stephane Eranian <[e-mail]>
Link: http://lkml.kernel.org/n/[e-mail]
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

tools/perf/ui/browsers/hists.c

···
 {
 	int color, width;
 	char folded_sign = callchain_list__folded(chain);
+	bool show_annotated = browser->show_dso && chain->ms.sym && symbol__annotation(chain->ms.sym)->src;
 
 	color = HE_COLORSET_NORMAL;
 	width = browser->b.width - (offset + 2);
···
 	ui_browser__set_color(&browser->b, color);
 	hist_browser__gotorc(browser, row, 0);
 	slsmg_write_nstring(" ", offset);
-	slsmg_printf("%c ", folded_sign);
+	slsmg_printf("%c", folded_sign);
+	ui_browser__write_graph(&browser->b, show_annotated ? SLSMG_RARROW_CHAR : ' ');
 	slsmg_write_nstring(str, width);
 }