[android] Make build_type a singleton.

build/android/pylib/fake_dns.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.
 
 import android_commands
 import constants
 import logging
 import os
 import subprocess
 import time
 
 
 class FakeDns(object):
   """Wrapper class for the fake_dns tool."""
   _FAKE_DNS_PATH = constants.TEST_EXECUTABLE_DIR + '/fake_dns'
 
-  def __init__(self, adb, build_type):
+  def __init__(self, adb):
     """
       Args:
         adb: the AndroidCommands to use.
-        build_type: 'Release' or 'Debug'.
     """
     self._adb = adb
-    self._build_type = build_type
     self._fake_dns = None
     self._original_dns = None
 
   def _PushAndStartFakeDns(self):
     """Starts the fake_dns server that replies all name queries 127.0.0.1.
 
     Returns:
       subprocess instance connected to the fake_dns process on the device.
     """
     self._adb.PushIfNeeded(
-        os.path.join(constants.DIR_SOURCE_ROOT, 'out', self._build_type,
+        os.path.join(constants.DIR_SOURCE_ROOT, 'out', constants.GetBuildType(),
                      'fake_dns'),
         FakeDns._FAKE_DNS_PATH)
     return subprocess.Popen(
         ['adb', '-s', self._adb._adb.GetSerialNumber(),
          'shell', '%s -D' % FakeDns._FAKE_DNS_PATH])
 
   def SetUp(self):
     """Configures the system to point to a DNS server that replies 127.0.0.1.
 
     This can be used in combination with the forwarder to forward all web
     traffic to a replay server.
 
     The TearDown() method will perform all cleanup.
     """
     self._adb.RunShellCommand('ip route add 8.8.8.0/24 via 127.0.0.1 dev lo')
     self._fake_dns = self._PushAndStartFakeDns()
     self._original_dns = self._adb.RunShellCommand('getprop net.dns1')[0]
     self._adb.RunShellCommand('setprop net.dns1 127.0.0.1')
     time.sleep(2)  # Time for server to start and the setprop to take effect.
 
   def TearDown(self):
     """Shuts down the fake_dns."""
     if self._fake_dns:
       if not self._original_dns or self._original_dns == '127.0.0.1':
         logging.warning('Bad original DNS, falling back to Google DNS.')
         self._original_dns = '8.8.8.8'
       self._adb.RunShellCommand('setprop net.dns1 %s' % self._original_dns)
       self._fake_dns.kill()
       self._adb.RunShellCommand('ip route del 8.8.8.0/24 via 127.0.0.1 dev lo')