Reland [telemetry] Timeline model cleanups

tools/telemetry/telemetry/core/timeline/event_container.py

Index: tools/telemetry/telemetry/core/timeline/event_container.py
diff --git a/tools/telemetry/telemetry/core/timeline/event_container.py b/tools/telemetry/telemetry/core/timeline/event_container.py
new file mode 100644
index 0000000000000000000000000000000000000000..bdde1845221972ea265092ba7fbc661e1b9f168f
--- /dev/null
+++ b/tools/telemetry/telemetry/core/timeline/event_container.py
@@ -0,0 +1,15 @@
+# Copyright (c) 2013 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+class TimelineEventContainer(object):
+  """Represents a container for events."""
+  def __init__(self, name, parent):
+    self.parent = parent
+    self.name = name
+
+  def IterChildContainers(self):
+    raise NotImplementedError()
+
+  def IterEventsInThisContainer(self):
+    raise NotImplementedError()