[Android] Add a configurable environment for devil/.

build/android/devil/android/sdk/dexdump.py

 # Copyright 2015 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 os
 
+from devil import env
 from devil.utils import cmd_helper
-from pylib import constants
 
-_DEXDUMP_PATH = os.path.join(constants.ANDROID_SDK_TOOLS, 'dexdump')
+_DEXDUMP_PATH = os.path.join(env.android_sdk.build_tools_path, 'dexdump')
 
 def DexDump(dexfiles, file_summary=False):
   """A wrapper around the Android SDK's dexdump tool.
 
   Args:
     dexfiles: The dexfile or list of dex files to dump.
     file_summary: Display summary information from the file header. (-f)
 
   Returns:
     An iterable over the output lines.
   """
   # TODO(jbudorick): Add support for more options as necessary.
   if isinstance(dexfiles, basestring):
     dexfiles = [dexfiles]
   args = [_DEXDUMP_PATH] + dexfiles
   if file_summary:
     args.append('-f')
 
   return cmd_helper.IterCmdOutputLines(args)