[Telemetry] Add API for updating ts_proxy_server's traffic settings

telemetry/telemetry/core/network_controller.py

Index: telemetry/telemetry/core/network_controller.py
diff --git a/telemetry/telemetry/core/network_controller.py b/telemetry/telemetry/core/network_controller.py
index 00cc9e69b42df39ae5cc5e8533af7284cb689787..da2e55a3d2735cbe2d4d8cd37b5650a32479efc3 100644
--- a/telemetry/telemetry/core/network_controller.py
+++ b/telemetry/telemetry/core/network_controller.py
@@ -23,6 +23,11 @@ class NetworkController(object):
   def Open(self, wpr_mode, extra_wpr_args):
     self._network_controller_backend.Open(wpr_mode, extra_wpr_args)
 
+  def UpdateTrafficSettings(self, round_trip_latency_ms=None,
+      download_bandwidth_kbps=None, upload_bandwidth_kbps=None):
+    self._network_controller_backend.ts_proxy_server.UpdateTrafficSettings(
+      round_trip_latency_ms, download_bandwidth_kbps, upload_bandwidth_kbps)
+
   @property
   def is_open(self):
     return self._network_controller_backend.is_open