Revert of Remove gyp-win-tool.

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.
 #
 # Copies the given "win tool" (which the toolchain uses to wrap compiler
 # invocations) and the environment blocks for the 32-bit and 64-bit builds on
 # Windows to the build directory.
 #
 # The arguments are the visual studio install location and the location of the
 # win tool. The script assumes that the root build directory is the current dir
@@ skipping 28 matching lines @@
   env = {}
   # This occasionally happens and leads to misleading SYSTEMROOT error messages
   # if not caught here.
   if output_of_set.count('=') == 0:
     raise Exception('Invalid output_of_set. Value is:\n%s' % output_of_set)
   for line in output_of_set.splitlines():
     for envvar in envvars_to_save:
       if re.match(envvar + '=', line.lower()):
         var, setting = line.split('=', 1)
         if envvar == 'path':
-          # Our own rules and actions in Chromium rely on python being in the
-          # path. Add the path to this python here so that if it's not in the
-          # path when ninja is run later, python will still be found.
+          # Our own rules (for running gyp-win-tool) and other actions in
+          # Chromium rely on python being in the path. Add the path to this
+          # python here so that if it's not in the path when ninja is run
+          # later, python will still be found.
           setting = os.path.dirname(sys.executable) + os.pathsep + setting
         env[var.upper()] = setting
         break
   if sys.platform in ('win32', 'cygwin'):
     for required in ('SYSTEMROOT', 'TEMP', 'TMP'):
       if required not in env:
         raise Exception('Environment variable "%s" '
                         'required to be set to valid path' % required)
   return env
 
@@ skipping 77 matching lines @@
   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():
     block += key + '=' + value + nul
   block += nul
   return block
 
 
+def _CopyTool(source_path):
+  """Copies the given tool to the current directory, including a warning not
+  to edit it."""
+  with open(source_path) as source_file:
+    tool_source = source_file.readlines()
+
+  # Add header and write it out to the current directory (which should be the
+  # root build dir). Don't write the file if a matching file already exists
+  # because that causes a cascade of unnecessary rebuilds.
+  match = False
+  contents = ''.join([tool_source[0],
+                      '# Generated by setup_toolchain.py do not edit.\n']
+                     + tool_source[1:])
+  out_path = 'gyp-win-tool'
+  try:
+    with open(out_path, 'rb') as read_tool_file:
+      existing_contents = read_tool_file.read()
+    if existing_contents == contents:
+      match = True
+  except:
+    pass
+  if not match:
+    with open(out_path, 'wb') as write_tool_file:
+      write_tool_file.write(contents)
+
+
 def main():
-  if len(sys.argv) != 6:
+  if len(sys.argv) != 7:
     print('Usage setup_toolchain.py '
-          '<visual studio path> <win sdk path> '
+          '<visual studio path> <win tool path> <win sdk path> '
           '<runtime dirs> <target_cpu> <include prefix>')
     sys.exit(2)
-  win_sdk_path = sys.argv[2]
-  runtime_dirs = sys.argv[3]
-  target_cpu = sys.argv[4]
-  include_prefix = sys.argv[5]
+  tool_source = sys.argv[2]
+  win_sdk_path = sys.argv[3]
+  runtime_dirs = sys.argv[4]
+  target_cpu = sys.argv[5]
+  include_prefix = sys.argv[6]
+
+  _CopyTool(tool_source)
 
   cpus = ('x86', 'x64')
   assert target_cpu in cpus
   vc_bin_dir = ''
   include = ''
 
   # TODO(scottmg|goma): Do we need an equivalent of
   # ninja_use_custom_environment_files?
 
   for cpu in cpus:
@@ skipping 24 matching lines @@
     with open('environment.winrt_' + cpu, 'wb') as f:
       f.write(env_block)
 
   assert vc_bin_dir
   print 'vc_bin_dir = ' + gn_helpers.ToGNString(vc_bin_dir)
   assert include
   print 'include_flags = ' + gn_helpers.ToGNString(include)
 
 if __name__ == '__main__':
   main()