Add a snapshot of flutter/engine/src/build to our sdk

build/toolchain/win/setup_toolchain.py

Index: build/toolchain/win/setup_toolchain.py
diff --git a/build/toolchain/win/setup_toolchain.py b/build/toolchain/win/setup_toolchain.py
new file mode 100644
index 0000000000000000000000000000000000000000..bc9bd1e7b43bf6fe65f5c34f36ac37aa71442c25
--- /dev/null
+++ b/build/toolchain/win/setup_toolchain.py
@@ -0,0 +1,154 @@
+# 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
+# and the files will be written to the current directory.
+
+import errno
+import os
+import re
+import subprocess
+import sys
+
+
+def _ExtractImportantEnvironment(output_of_set):
+  """Extracts environment variables required for the toolchain to run from
+  a textual dump output by the cmd.exe 'set' command."""
+  envvars_to_save = (
+      'goma_.*', # TODO(scottmg): This is ugly, but needed for goma.
+      'include',
+      'lib',
+      'libpath',
+      'path',
+      'pathext',
+      'systemroot',
+      'temp',
+      'tmp',
+      )
+  env = {}
+  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 (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
+  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
+
+
+def _SetupScript(target_cpu, sdk_dir):
+  """Returns a command (with arguments) to be used to set up the
+  environment."""
+  # Check if we are running in the SDK command line environment and use
+  # the setup script from the SDK if so. |target_cpu| should be either
+  # 'x86' or 'x64'.
+  assert target_cpu 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_cpu]
+  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(os.environ['GYP_MSVS_OVERRIDE_PATH'],
+                                          'VC/vcvarsall.bat')),
+            'amd64_x86' if target_cpu == '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():
+    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).
+  with open("gyp-win-tool", 'w') as tool_file:
+    tool_file.write(''.join([tool_source[0],
+                             '# Generated by setup_toolchain.py do not edit.\n']
+                            + tool_source[1:]))
+
+
+def main():
+  if len(sys.argv) != 6:
+    print('Usage setup_toolchain.py '
+          '<visual studio path> <win tool path> <win sdk path> '
+          '<runtime dirs> <target_cpu>')
+    sys.exit(2)
+  tool_source = sys.argv[2]
+  win_sdk_path = sys.argv[3]
+  runtime_dirs = sys.argv[4]
+  target_cpu = sys.argv[5]
+
+  _CopyTool(tool_source)
+
+  cpus = ('x86', 'x64')
+  assert target_cpu in cpus
+  vc_bin_dir = ''
+
+  # TODO(scottmg|goma): Do we need an equivalent of
+  # ninja_use_custom_environment_files?
+
+  for cpu in cpus:
+    # Extract environment variables for subprocesses.
+    args = _SetupScript(cpu, win_sdk_path)
+    args.extend(('&&', 'set'))
+    popen = subprocess.Popen(
+        args, shell=True, stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
+    variables, _ = popen.communicate()
+    env = _ExtractImportantEnvironment(variables)
+    env['PATH'] = runtime_dirs + ';' + env['PATH']
+
+    if cpu == target_cpu:
+      for path in env['PATH'].split(os.pathsep):
+        if os.path.exists(os.path.join(path, 'cl.exe')):
+          vc_bin_dir = os.path.realpath(path)
+          break
+
+    # The Windows SDK include directories must be first. They both have a sal.h,
+    # and the SDK one is newer and the SDK uses some newer features from it not
+    # present in the Visual Studio one.
+
+    if win_sdk_path:
+      additional_includes = ('{sdk_dir}\\Include\\shared;' +
+                             '{sdk_dir}\\Include\\um;' +
+                             '{sdk_dir}\\Include\\winrt;').format(
+                                  sdk_dir=win_sdk_path)
+      env['INCLUDE'] = additional_includes + env['INCLUDE']
+    env_block = _FormatAsEnvironmentBlock(env)
+    with open('environment.' + cpu, 'wb') as f:
+      f.write(env_block)
+
+  assert vc_bin_dir
+  print 'vc_bin_dir = "%s"' % vc_bin_dir
+
+
+if __name__ == '__main__':
+  main()