Following the depot_tools tutorial, `fetch chromium` ends with an error on my Windows 10 system.

Non-Googlers can avoid this by first setting DEPOT_TOOLS_WIN_TOOLCHAIN=0 as described in the Windows build instructions[1]. This is not obvious, since the first instruction in that doc is to check out Chromium. The error message should be more useful.

Googlers should run `download_from_google_storage --config` *after* running fetch, meaning they would run fetch, then encounter this error, then run gclient sync again. Again, the error message should be more useful, or there should be some command to run *before* fetch that would bypass the error altogether. (Running `download_from_google_storage --config` before `fetch` results in an error on my machine (The system cannot find the path specified) even though Python is installed.)

The output was:

D:\dev\projects\chromium\c>fetch chromium
Running: 'D:\dev\projects\chromium\depot_tools\python276_bin\python.exe' 'D:\dev\projects\chromium\depot_tools\gclient.py' root
Running: 'D:\dev\projects\chromium\depot_tools\python276_bin\python.exe' 'D:\dev\projects\chromium\depot_tools\gclient.py' config --spec 'solutions = [
  {
    "url": "https://chromium.googlesource.com/chromium/src.git",
    "managed": False,
    "name": "src",
    "deps_file": ".DEPS.git",
    "custom_deps": {},
  },
]
'
Running: 'D:\dev\projects\chromium\depot_tools\python276_bin\python.exe' 'D:\dev\projects\chromium\depot_tools\gclient.py' sync
Error: Command 'D:\\dev\\projects\\chromium\\depot_tools\\python276_bin\\python.exe src/build/landmines.py' returned non-zero exit status 1 in D:\dev\projects\chromium\c
Traceback (most recent call last):
  File "D:\dev\projects\chromium\depot_tools\\fetch.py", line 353, in <module>
    sys.exit(main())
  File "D:\dev\projects\chromium\depot_tools\\fetch.py", line 348, in main
    return run(options, spec, root)
  File "D:\dev\projects\chromium\depot_tools\\fetch.py", line 342, in run
    return checkout.init()
  File "D:\dev\projects\chromium\depot_tools\\fetch.py", line 142, in init
    self.run_gclient(*sync_cmd)
  File "D:\dev\projects\chromium\depot_tools\\fetch.py", line 76, in run_gclient
    return self.run(cmd_prefix + cmd, **kwargs)
  File "D:\dev\projects\chromium\depot_tools\\fetch.py", line 66, in run
    return subprocess.check_output(cmd, **kwargs)
  File "D:\dev\projects\chromium\depot_tools\python276_bin\lib\subprocess.py", line 573, in check_output
    raise CalledProcessError(retcode, cmd, output=output)
subprocess.CalledProcessError: Command '('D:\\dev\\projects\\chromium\\depot_tools\\python276_bin\\python.exe', 'D:\\dev\\projects\\chromium\\depot_tools\\gclient.py', 'sync')' returned non-zero exit status 2


[1] https://chromium.googlesource.com/chromium/src/+/master/docs/windows_build_instructions.md