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

chrome/test/tab_switching/tab_switching_test.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.
 
 Import('env')
 
 env = env.Clone()
 
 env.ApplySConscript([
     '$BASE_DIR/using_base.scons',
@@ skipping 16 matching lines @@
         '$CHROME_SRC_DIR',
     ],
     LIBS = [
         'automation',
         'browser',
         'browser_views',
         'common',
     ],
 )
 
-if env['PLATFORM'] == 'win32':
+if env.Bit('windows'):
   env.Prepend(
       LINKFLAGS = [
           '/INCREMENTAL',
           '/DEBUG',
 
           '/DELAYLOAD:"dwmapi.dll"',
           '/DELAYLOAD:"uxtheme.dll"',
 
           '/MACHINE:X86',
           '/FIXED:No',
@@ skipping 16 matching lines @@
     '$CHROME_DIR/test/ui/run_all_unittests$OBJSUFFIX',
     '$CHROME_DIR/test/ui/ui_test$OBJSUFFIX',
     '$CHROME_DIR/test/ui/ui_test_suite$OBJSUFFIX',
     'tab_switching_test.cc',
 ]
 
 #"..\..\Debug\obj\tab_switching_test\precompiled_wtl.obj"
 
 env.ChromeTestProgram('tab_switching_test', input_files)