Add trace events for some of telemetry internal functions

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 88244e18467012c972b69dba0d44a0cca190edfe..6eb357cda3cd3d7240fa1d054d9277d529ecd70d 100644
--- a/telemetry/telemetry/core/network_controller.py
+++ b/telemetry/telemetry/core/network_controller.py
@@ -2,6 +2,9 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
+from py_trace_event import trace_event
+
+
 class NetworkController(object):
   """Control network settings and servers to simulate the Web.
 
@@ -9,6 +12,8 @@ class NetworkController(object):
   Web Page Replay is used to record and replay HTTP/HTTPS responses.
   """
 
+  __metaclass__ = trace_event.TracedMetaClass
+
   def __init__(self, network_controller_backend):
     self._network_controller_backend = network_controller_backend