[DO NOT COMMIT] Refactor systrace to support new clock sync design

systrace/systrace/__init__.py

Index: systrace/systrace/__init__.py
diff --git a/systrace/systrace/__init__.py b/systrace/systrace/__init__.py
index ca3e206fdd8f2b8e5facc81da817abd7d2ca143e..5c2e68304eb2878a3f9aa7c972d6c343d1eb5706 100644
--- a/systrace/systrace/__init__.py
+++ b/systrace/systrace/__init__.py
@@ -1,3 +1,26 @@
 # Copyright 2016 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.
+import os
+import sys
+
+def _JoinPath(*path_parts):
+  return os.path.abspath(os.path.join(*path_parts))
+
+
+def _AddDirToPythonPath(*path_parts):
+  path = _JoinPath(*path_parts)
+  if os.path.isdir(path) and path not in sys.path:
+    # Some call sites that use Telemetry assume that sys.path[0] is the
+    # directory containing the script, so we add these extra paths to right
+    # after sys.path[0].
+    sys.path.insert(1, path)
+
+_CATAPULT_DIR = os.path.join(
+    os.path.dirname(os.path.abspath(__file__)), os.path.pardir, os.path.pardir)
+
+_AddDirToPythonPath(_CATAPULT_DIR, 'catapult_base')
+_AddDirToPythonPath(_CATAPULT_DIR, 'devil')
+_AddDirToPythonPath(_CATAPULT_DIR, 'systrace')
+_AddDirToPythonPath(_CATAPULT_DIR, 'common', 'py_trace_event')
+_AddDirToPythonPath(_CATAPULT_DIR, 'common', 'py_trace_event', 'py_trace_event')