Update from https://crrev.com/302630

build/android/pylib/cmd_helper.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.
 
 """A wrapper for subprocess to make calling shell commands easier."""
 
 import logging
 import os
 import pipes
 import select
@@ skipping 97 matching lines @@
     shell: Whether to execute args as a shell command.
 
   Returns:
     Captures and returns the command's stdout.
     Prints the command's stderr to logger (which defaults to stdout).
   """
   (_, output) = GetCmdStatusAndOutput(args, cwd, shell)
   return output
 
 
+def _LogCommand(args, cwd=None):
+  if not isinstance(args, basestring):
+    args = ' '.join(SingleQuote(c) for c in args)
+  if cwd is None:
+    cwd = ''
+  else:
+    cwd = ':' + cwd
+  logging.info('[host]%s> %s', cwd, args)
+
+
 def GetCmdStatusAndOutput(args, cwd=None, shell=False):
   """Executes a subprocess and returns its exit code and output.
 
   Args:
     args: A string or a sequence of program arguments. The program to execute is
       the string or the first item in the args sequence.
     cwd: If not None, the subprocess's current directory will be changed to
       |cwd| before it's executed.
     shell: Whether to execute args as a shell command.
 
   Returns:
     The 2-tuple (exit code, output).
   """
   if isinstance(args, basestring):
-    args_repr = args
     if not shell:
       raise Exception('string args must be run with shell=True')
   elif shell:
     raise Exception('array args must be run with shell=False')
-  else:
-    args_repr = ' '.join(map(SingleQuote, args))
 
-  s = '[host]'
-  if cwd:
-    s += ':' + cwd
-  s += '> ' + args_repr
-  logging.info(s)
+  _LogCommand(args, cwd)
   pipe = Popen(args, stdout=subprocess.PIPE, stderr=subprocess.PIPE,
                shell=shell, cwd=cwd)
   stdout, stderr = pipe.communicate()
 
   if stderr:
     logging.critical(stderr)
   if len(stdout) > 4096:
     logging.debug('Truncated output:')
   logging.debug(stdout[:4096])
   return (pipe.returncode, stdout)
@@ skipping 15 matching lines @@
     cwd: If not None, the subprocess's current directory will be changed to
       |cwd| before it's executed.
     shell: Whether to execute args as a shell command.
     logfile: Optional file-like object that will receive output from the
       command as it is running.
 
   Returns:
     The 2-tuple (exit code, output).
   """
   assert fcntl, 'fcntl module is required'
+  if isinstance(args, basestring):
+    if not shell:
+      raise Exception('string args must be run with shell=True')
+  elif shell:
+    raise Exception('array args must be run with shell=False')
+
+  _LogCommand(args, cwd)
   process = Popen(args, cwd=cwd, shell=shell, stdout=subprocess.PIPE,
                   stderr=subprocess.STDOUT)
   try:
     end_time = (time.time() + timeout) if timeout else None
     poll_interval = 1
     buffer_size = 4096
     child_fd = process.stdout.fileno()
     output = StringIO.StringIO()
 
     # Enable non-blocking reads from the child's stdout.
@@ skipping 15 matching lines @@
         break
   finally:
     try:
       # Make sure the process doesn't stick around if we fail with an
       # exception.
       process.kill()
     except OSError:
       pass
     process.wait()
   return process.returncode, output.getvalue()