[Telemetry] Move discover to common/py_utils

telemetry/telemetry/internal/platform/tracing_controller_backend.py

 # Copyright 2014 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 ast
 from telemetry.internal.util import atexit_with_log
 import contextlib
 import gc
 import logging
 import os
 import sys
 import tempfile
 import traceback
 import uuid
 
 from py_trace_event import trace_event
-from telemetry.core import discover
+from py_utils import discover
 from telemetry.core import exceptions
 from telemetry.core import util
 from telemetry.internal.platform import tracing_agent
 from telemetry.internal.platform.tracing_agent import chrome_tracing_agent
 from telemetry.timeline import tracing_config
 from tracing.trace_data import trace_data as trace_data_module
 
 
 def _IterAllTracingAgentClasses():
   tracing_agent_dir = os.path.join(
@@ skipping 256 matching lines @@
     try:
       os.remove(self._trace_log)
       self._trace_log = None
     except OSError:
       logging.exception('Error when deleting %s, will try again at exit.',
                         self._trace_log)
       def DeleteAtExit(path):
         os.remove(path)
       atexit_with_log.Register(DeleteAtExit, self._trace_log)
     self._trace_log = None