Isolate base_unittests_apk.

build/android/android.isolate

 # 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.
 {
   'variables': {
     'files': [
       '../../build/util/lib/common/',
       '../../third_party/android_tools/sdk/build-tools/',
       '../../third_party/android_tools/sdk/platform-tools/',
       '../../third_party/appurify-python/',
       '../../third_party/requests/',
+      '../../tools/swarming_client/',
       '<(PRODUCT_DIR)/md5sum_bin_host',
       '<(PRODUCT_DIR)/md5sum_dist/',
       'devil/',
       'lighttpd_server.py',
       'pylib/',
       'test_runner.py',
     ]
   }
 }