[Telemetry] discover.DiscoverClasses() does not add inherited classes.

tools/telemetry/unittest_data/discoverable_classes/another_discover_dummyclass.py

Index: tools/telemetry/unittest_data/discoverable_classes/another_discover_dummyclass.py
diff --git a/tools/telemetry/unittest_data/discoverable_classes/another_discover_dummyclass.py b/tools/telemetry/unittest_data/discoverable_classes/another_discover_dummyclass.py
new file mode 100644
index 0000000000000000000000000000000000000000..f596d80cc5e33cfb7bde79086cea6ca585b9cf45
--- /dev/null
+++ b/tools/telemetry/unittest_data/discoverable_classes/another_discover_dummyclass.py
@@ -0,0 +1,16 @@
+# 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.
+
+"""Another dummy exception subclasses used by core/discover.py's unit tests."""
+
+# Import class instead of module explicitly so that inspect.getmembers() returns
+# two Exception subclasses in this current file.
+# Suppress complaints about unable to import class.  The directory path is
+# added at runtime by telemetry test runner.
+#pylint: disable=F0401
+from discoverable_classes.discover_dummyclass import DummyException
+
+
+class AnotherDummyException(DummyException):
+  pass