Add infrastructure to run tests on android.

mojo/tools/mopy/file_hash.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.
+
+import logging
+
+# pylint: disable=E0611
+from hashlib import sha256
+
+from mopy.memoize import memoize
+
+_logging = logging.getLogger()
+
+@memoize
+def file_hash(filename):
+  """Returns a string representing the hash of the given file."""
+  _logging.debug("Hashing %s ...", filename)
+  with open(filename, mode='rb') as f:
+    m = sha256()
+    while True:
+      block = f.read(4096)
+      if not block:
+        break
+      m.update(block)
+  _logging.debug("  => %s", m.hexdigest())
+  return m.hexdigest()