Convert from using env['PLATFORM'] directly to using the more flexible...

net/stress_cache.scons

 # Copyright (c) 2006-2008 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.
 
 __doc__ = """
 Configuration for building the stress_cache{,.exe} executable.
 """
 
 Import('env')
 
 env = env.Clone()
 
 env.ApplySConscript([
     '$BASE_DIR/using_base.scons',
     '$GTEST_DIR/../using_gtest.scons',
     '$ICU38_DIR/using_icu38.scons',
     '$NET_DIR/using_net.scons',
 ])
 
-if env['PLATFORM'] in ('darwin', 'posix'):
+if env.Bit('posix'):
   env.ApplySConscript(['$THIRD_PARTY_DIR/libevent/using_libevent.scons'])
 
 env.Prepend(
     CPPPATH = [
         '$CHROME_SRC_DIR',
     ],
 )
 
-if env['PLATFORM'] == 'win32':
+if env.Bit('windows'):
   env.Prepend(
       CCFLAGS = [
           '/WX',
       ],
   )
 
 input_files = [
     'disk_cache/disk_cache_test_util$OBJSUFFIX',
     'disk_cache/stress_cache.cc',
 ]
 
-if env['PLATFORM'] in ('posix', 'win32'):
+if not env.Bit('mac'):
   env.ChromeTestProgram('stress_cache', input_files)