[Android] Split uiautomator test runner from instrumentation.

build/android/pylib/base/base_test_runner.py

 # Copyright (c) 2012 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.
 
+"""Base class for running tests on a single device."""
+
 import contextlib
 import httplib
 import logging
 import os
 import tempfile
 import time
 
 from pylib import android_commands
 from pylib import constants
 from pylib import ports
@@ skipping 191 matching lines @@
       # Wait for 2 seconds then restart.
       time.sleep(2)
     if not server_ready:
       logging.error(';'.join(error_msgs))
       raise Exception('Can not start the test spawner server.')
     self._PushTestServerPortInfoToDevice()
     self._spawner_forwarder = self._CreateAndRunForwarder(
         self.adb,
         [(self.test_server_spawner_port, self.test_server_spawner_port)],
         self.tool, '127.0.0.1', self.build_type)