Add --test-jar arg to test_runner to explicitly specify its path.

build/android/pylib/instrumentation/instrumentation_test_instance.py

 # Copyright 2015 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 collections
 import copy
 import logging
 import os
 import pickle
 import re
@@ skipping 469 matching lines @@
 
     self._apk_under_test_incremental_install_script = (
         args.apk_under_test_incremental_install_script)
     self._test_apk_incremental_install_script = (
         args.test_apk_incremental_install_script)
 
     if self._test_apk_incremental_install_script:
       assert self._suite.endswith('_incremental')
       self._suite = self._suite[:-len('_incremental')]
 
-    self._test_jar = os.path.join(
-        constants.GetOutDirectory(), constants.SDK_BUILD_TEST_JAVALIB_DIR,
-        '%s.jar' % self._suite)
+    self._test_jar = args.test_jar
     self._test_support_apk = apk_helper.ToHelper(os.path.join(
         constants.GetOutDirectory(), constants.SDK_BUILD_TEST_JAVALIB_DIR,
         '%sSupport.apk' % self._suite))
 
     if not os.path.exists(self._test_apk.path):
       error_func('Unable to find test APK: %s' % self._test_apk.path)
-    if not os.path.exists(self._test_jar):
+    if not self._test_jar or not os.path.exists(self._test_jar):
       error_func('Unable to find test JAR: %s' % self._test_jar)
 
     self._test_package = self._test_apk.GetPackageName()
     self._test_runner = self._test_apk.GetInstrumentationName()
 
     self._package_info = None
     if self._apk_under_test:
       package_under_test = self._apk_under_test.GetPackageName()
       for package_info in constants.PACKAGE_INFO.itervalues():
         if package_under_test == package_info.package:
@@ skipping 233 matching lines @@
 
   @staticmethod
   def GenerateTestResults(
       result_code, result_bundle, statuses, start_ms, duration_ms):
     return GenerateTestResults(result_code, result_bundle, statuses,
                                start_ms, duration_ms)
 
   #override
   def TearDown(self):
     pass