Update from https://crrev.com/333737

build/android/pylib/utils/md5sum.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 collections
 import logging
 import os
 import re
 import tempfile
 import types
 
 from pylib import cmd_helper
 from pylib import constants
 from pylib.utils import device_temp_file
 
 MD5SUM_DEVICE_LIB_PATH = '/data/local/tmp/md5sum/'
 MD5SUM_DEVICE_BIN_PATH = MD5SUM_DEVICE_LIB_PATH + 'md5sum_bin'
 
 MD5SUM_DEVICE_SCRIPT_FORMAT = (
     'test -f {path} -o -d {path} '
     '&& LD_LIBRARY_PATH={md5sum_lib} {md5sum_bin} {path}')
 
-_STARTS_WITH_CHECKSUM_RE = re.compile(r'^\s*[0-9a-fA-f]{32}\s+')
+_STARTS_WITH_CHECKSUM_RE = re.compile(r'^\s*[0-9a-fA-F]{32}\s+')
 
 
 def CalculateHostMd5Sums(paths):
   """Calculates the MD5 sum value for all items in |paths|.
 
+  Directories are traversed recursively and the MD5 sum of each file found is
+  reported in the result.
+
   Args:
     paths: A list of host paths to md5sum.
   Returns:
-    A dict mapping paths to their respective md5sum checksums.
+    A dict mapping file paths to their respective md5sum checksums.
   """
   if isinstance(paths, basestring):
     paths = [paths]
 
   md5sum_bin_host_path = os.path.join(
       constants.GetOutDirectory(), 'md5sum_bin_host')
   if not os.path.exists(md5sum_bin_host_path):
     raise IOError('File not built: %s' % md5sum_bin_host_path)
   out = cmd_helper.GetCmdOutput([md5sum_bin_host_path] + [p for p in paths])
 
   return _ParseMd5SumOutput(out.splitlines())
 
 
 def CalculateDeviceMd5Sums(paths, device):
   """Calculates the MD5 sum value for all items in |paths|.
 
+  Directories are traversed recursively and the MD5 sum of each file found is
+  reported in the result.
+
   Args:
     paths: A list of device paths to md5sum.
   Returns:
-    A dict mapping paths to their respective md5sum checksums.
+    A dict mapping file paths to their respective md5sum checksums.
   """
   if isinstance(paths, basestring):
     paths = [paths]
 
   if not device.FileExists(MD5SUM_DEVICE_BIN_PATH):
     md5sum_dist_path = os.path.join(constants.GetOutDirectory(), 'md5sum_dist')
     if not os.path.exists(md5sum_dist_path):
       raise IOError('File not built: %s' % md5sum_dist_path)
     device.adb.Push(md5sum_dist_path, MD5SUM_DEVICE_LIB_PATH)
 
@@ skipping 13 matching lines @@
       out = device.RunShellCommand(['sh', md5sum_device_script_file.name])
 
   return _ParseMd5SumOutput(out)
 
 
 def _ParseMd5SumOutput(out):
   hash_and_path = (l.split(None, 1) for l in out
                    if l and _STARTS_WITH_CHECKSUM_RE.match(l))
   return dict((p, h) for h, p in hash_and_path)