Refactor/cleanup WebRTC-specific Andorid glue code.

build/android/pylib/constants.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.
 
 """Defines a set of constants shared by test runners and other scripts."""
 # pylint: disable=W0212
 
 import collections
 import logging
 import os
 import subprocess
 
 
-DIR_SOURCE_ROOT = os.path.abspath(os.path.join(os.path.dirname(__file__),
-                                               os.pardir, os.pardir, os.pardir))
+DIR_SOURCE_ROOT = os.environ.get('CHECKOUT_SOURCE_ROOT',
+    os.path.abspath(os.path.join(os.path.dirname(__file__),
+                                 os.pardir, os.pardir, os.pardir)))
 ISOLATE_DEPS_DIR = os.path.join(DIR_SOURCE_ROOT, 'isolate_deps_dir')
 
 CHROME_SHELL_HOST_DRIVEN_DIR = os.path.join(
     DIR_SOURCE_ROOT, 'chrome', 'android')
 
 
 PackageInfo = collections.namedtuple('PackageInfo',
     ['package', 'activity', 'cmdline_file', 'devtools_socket',
      'test_package'])
 
@@ skipping 178 matching lines @@
       subprocess.call(['adb', 'version'], stdout=devnull, stderr=devnull)
     return 'adb'
   except OSError:
     logging.debug('No adb found in $PATH, fallback to checked in binary.')
     return os.path.join(ANDROID_SDK_ROOT, 'platform-tools', 'adb')
 
 
 # Exit codes
 ERROR_EXIT_CODE = 1
 WARNING_EXIT_CODE = 88