Hooks for Electron output UTF-8 characters.
Example error for when "✔" is output:
  File "/home/markus/depot_tools/metrics.py", line 266, in print_notice_and_exit
    yield
  File "/home/markus/depot_tools/gclient.py", line 3112, in <module>
    sys.exit(main(sys.argv[1:]))
  File "/home/markus/depot_tools/gclient.py", line 3098, in main
    return dispatcher.execute(OptionParser(), argv)
  File "/home/markus/depot_tools/subcommand.py", line 252, in execute
    return command(parser, args[1:])
  File "/home/markus/depot_tools/gclient.py", line 2677, in CMDsync
    ret = client.RunOnDeps('update', args)
  File "/home/markus/depot_tools/gclient.py", line 1746, in RunOnDeps
    self.RunHooksRecursively(self._options, pm)
  File "/home/markus/depot_tools/gclient.py", line 1052, in RunHooksRecursively
    hook.run()
  File "/home/markus/depot_tools/gclient.py", line 245, in run
    cmd, cwd=self.effective_cwd, always=self._verbose)
  File "/home/markus/depot_tools/gclient_utils.py", line 344, in CheckCallAndFilterAndHeader
    return CheckCallAndFilter(args, **kwargs)
  File "/home/markus/depot_tools/gclient_utils.py", line 576, in CheckCallAndFilter
    stdout.write(in_byte.decode())
  File "/usr/lib/python2.7/encodings/utf_8.py", line 16, in decode
    return codecs.utf_8_decode(input, errors, True)
UnicodeDecodeError: 'utf8' codec can't decode byte 0xe2 in position 0: unexpected end of data

This issue was introduced in CL:1524583.

Bug: 942522
Change-Id: I3c4355b925b34398c800d142f942531a829e0297
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/1541334
Auto-Submit: Raul Tambre <raul@tambre.ee>
Reviewed-by: Dirk Pranke <dpranke@chromium.org>
Commit-Queue: Raul Tambre <raul@tambre.ee>