[Android] Implement gtest and local in platform mode.

build/android/pylib/base/test_run_factory.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.
 
-def CreateTestRun(_args, _env, _test_instance, error_func):
+from pylib.gtest import gtest_test_instance
+from pylib.gtest import local_device_gtest_run
+from pylib.local.device import local_device_environment
 
-  # TODO(jbudorick) Add local gtest test runs
-  # TODO(jbudorick) Add local instrumentation test runs.
-  error_func('No test runs are currently supported.')
 
+def CreateTestRun(_args, env, test_instance, error_func):
+  if isinstance(env, local_device_environment.LocalDeviceEnvironment):
+    if isinstance(test_instance, gtest_test_instance.GtestTestInstance):
+      return local_device_gtest_run.LocalDeviceGtestRun(env, test_instance)
+
+  # TODO(jbudorick): Add local instrumentation test runs.
+  # TODO(rnephew): Add remote_device instrumentation test runs.
+
+  error_func('Unable to create test run for %s tests in %s environment'
+             % (str(test_instance), str(env)))
+