[Android] Add a configurable environment for devil/.

build/android/devil/utils/mock_calls.py

Index: build/android/devil/utils/mock_calls.py
diff --git a/build/android/devil/utils/mock_calls.py b/build/android/devil/utils/mock_calls.py
index 59167bacbf1b047c9200e00490917bf02e2b67c4..10aef31a6dbba5c7808ea6b0e36dbbf547f3cd1a 100644
--- a/build/android/devil/utils/mock_calls.py
+++ b/build/android/devil/utils/mock_calls.py
@@ -6,14 +6,12 @@
 A test facility to assert call sequences while mocking their behavior.
 """
 
-import os
 import sys
 import unittest
 
-from pylib import constants
+from devil import env
 
-sys.path.append(os.path.join(
-    constants.DIR_SOURCE_ROOT, 'third_party', 'pymock'))
+sys.path.append(env.dependencies.pymock_path)
 import mock # pylint: disable=F0401