Improvements to UI to python event log analyzer tool.

SSRCs are now filtered by incoming and outgoing.

NOTRY=True

Review-Url: https://codereview.webrtc.org/2310063002
Cr-Commit-Position: refs/heads/master@{#14092}
diff --git a/webrtc/tools/py_event_log_analyzer/misc.py b/webrtc/tools/py_event_log_analyzer/misc.py
index 50ac28e..bd70b75 100644
--- a/webrtc/tools/py_event_log_analyzer/misc.py
+++ b/webrtc/tools/py_event_log_analyzer/misc.py
@@ -72,6 +72,14 @@
                            mod // 2) % mod - (mod // 2)
   return lst
 
+
+def ssrc_directions(data_points):
+  ssrc_is_incoming = {}
+  for point in data_points:
+    ssrc_is_incoming[point.ssrc] = point.incoming
+  return ssrc_is_incoming
+
+
 # Python 2/3-compatible input function
 if sys.version_info[0] <= 2:
   get_input = raw_input