Add trace events for some of telemetry internal functions

telemetry/telemetry/story/shared_state.py

Index: telemetry/telemetry/story/shared_state.py
diff --git a/telemetry/telemetry/story/shared_state.py b/telemetry/telemetry/story/shared_state.py
index 8af1d8b5860633fd6d5daa4aa1808ea5565ab9db..9de494558e7875e7d0fc128c16565369808318f7 100644
--- a/telemetry/telemetry/story/shared_state.py
+++ b/telemetry/telemetry/story/shared_state.py
@@ -2,6 +2,8 @@
 # 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 SharedState(object):
   """A class that manages the test state across multiple stories.
@@ -9,6 +11,8 @@ class SharedState(object):
 
   """
 
+  __metaclass__ = trace_event.TracedMetaClass
+
   def __init__(self, test, options, story_set):
     """ This method is styled on unittest.TestCase.setUpClass.
     Override to do any action before running stories that