WIP: Add support for additional flag-specified tracing categories.

common/py_utils/py_utils/class_util.py

Index: common/py_utils/py_utils/class_util.py
diff --git a/common/py_utils/py_utils/class_util.py b/common/py_utils/py_utils/class_util.py
new file mode 100644
index 0000000000000000000000000000000000000000..4cec430038bf525b9f34563dff877d16257fe4e7
--- /dev/null
+++ b/common/py_utils/py_utils/class_util.py
@@ -0,0 +1,26 @@
+# Copyright 2017 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 inspect
+
+def IsMethodOverridden(parent_cls, child_cls, method_name):
+  assert inspect.isclass(parent_cls), '%s should be a class' % parent_cls
+  assert inspect.isclass(child_cls), '%s should be a class' % child_cls
+  assert parent_cls.__dict__.get(method_name), '%s has no method %s' % (
+      parent_cls, method_name)
+
+  if child_cls.__dict__.get(method_name):
+    # It's overridden
+    return True
+
+  if parent_cls in child_cls.__bases__:
+    # The parent is the base class of the child, we did not find the
+    # overridden method.
+    return False
+
+  # For all the base classes of this class that are not object, check if
+  # they override the method.
+  base_cls = [cls for cls in child_cls.__bases__ if cls and cls != object]
+  return any(
+      IsMethodOverridden(parent_cls, base, method_name) for base in base_cls)