win gn: Semi-support for non-depot_tools toolchain

build/toolchain/win/setup_toolchain.py

 # Copyright (c) 2013 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 errno
 import os
 import re
 import subprocess
 import sys
 
@@ skipping 49 matching lines @@
   # the setup script from the SDK if so. |target_arch| should be either
   # 'x86' or 'x64'.
   assert target_arch in ('x86', 'x64')
   if bool(int(os.environ.get('DEPOT_TOOLS_WIN_TOOLCHAIN', 1))) and sdk_dir:
     return [os.path.normpath(os.path.join(sdk_dir, 'Bin/SetEnv.Cmd')),
             '/' + target_arch]
   else:
     # We only support x64-hosted tools.
     # TODO(scottmg|dpranke): Non-depot_tools toolchain: need to get Visual
     # Studio install location from registry.
-    return [os.path.normpath(os.path.join(FIND_VS_IN_REG, 'VC/vcvarsall.bat')),
+    return [os.path.normpath(os.path.join(os.environ['GYP_MSVS_OVERRIDE_PATH'],
+                                          'VC/vcvarsall.bat')),
             'amd64_x86' if target_arch == 'x86' else 'amd64']
 
 
 def _FormatAsEnvironmentBlock(envvar_dict):
   """Format as an 'environment block' directly suitable for CreateProcess.
   Briefly this is a list of key=value\0, terminated by an additional \0. See
   CreateProcess documentation for more details."""
   block = ''
   nul = '\0'
   for key, value in envvar_dict.iteritems():
@@ skipping 59 matching lines @@
     env_block = _FormatAsEnvironmentBlock(env)
     with open('environment.' + arch, 'wb') as f:
       f.write(env_block)
 
   assert vc_bin_dir
   print 'vc_bin_dir = "%s"' % vc_bin_dir
 
 
 if __name__ == '__main__':
   main()