perf report: Fix a no annotate browser displayed issue

When enabling '-b' option in perf record, for example,

  perf record -b ...
  perf report

and then browsing the annotate browser from perf report (press 'A'), it
would fail (annotate browser can't be displayed).

It's because the '.add_entry_cb' op of struct report is overwritten by
hist_iter__branch_callback() in builtin-report.c. But this function doesn't do
something like mapping symbols and sources. So next, do_annotate() will return
directly.

        notes = symbol__annotation(act->ms.sym);
        if (!notes->src)
                return 0;

This patch adds the lost code to hist_iter__branch_callback (refer to
hist_iter__report_callback).

v2:

Fix a crash bug when perform 'perf report --stdio'.

The reason is that we init the symbol annotation only in browser mode, it
doesn't allocate/init resources for stdio mode.

So now in hist_iter__branch_callback(), it will return directly if it's not in
browser mode.

Signed-off-by: Jin Yao <yao.jin@linux.intel.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1514284963-18587-1-git-send-email-yao.jin@linux.intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/builtin-report.c

@@ -162,12 +162,28 @@ static int hist_iter__branch_callback(struct hist_entry_iter *iter,
 	struct hist_entry *he = iter->he;
 	struct report *rep = arg;
 	struct branch_info *bi;
+	struct perf_sample *sample = iter->sample;
+	struct perf_evsel *evsel = iter->evsel;
+	int err;
+
+	if (!ui__has_annotation())
+		return 0;
+
+	hist__account_cycles(sample->branch_stack, al, sample,
+			     rep->nonany_branch_mode);
 
 	bi = he->branch_info;
+	err = addr_map_symbol__inc_samples(&bi->from, sample, evsel->idx);
+	if (err)
+		goto out;
+
+	err = addr_map_symbol__inc_samples(&bi->to, sample, evsel->idx);
+
 	branch_type_count(&rep->brtype_stat, &bi->flags,
 			  bi->from.addr, bi->to.addr);
 
-	return 0;
+out:
+	return err;
 }
 
 static int process_sample_event(struct perf_tool *tool,