This just happened on the CQ:

[10350/36729] ACTION //services/device/public/interfaces:interfaces__generator(//build/toolchain/win:win_clang_x86)
FAILED: gen/services/device/public/interfaces/hid.mojom.cc gen/services/device/public/interfaces/hid.mojom.h gen/services/device/public/interfaces/hid.mojom.srcjar 
C:/b/depot_tools/win_tools-2_7_6_bin/python/bin/python.exe ../../mojo/public/tools/bindings/mojom_bindings_generator.py --use_bundled_pylibs generate ../../services/device/public/interfaces/hid.mojom -d ../../ -I ../../ -o gen --bytecode_path gen/mojo/public/tools/bindings --scrambled_message_id_salt_path ../../chrome/VERSION --allow_native_structs -g c++,java --depfile gen/services/device/public/interfaces/interfaces__generator_hid.d --depfile_target gen/services/device/public/interfaces/hid.mojom.cc --typemap gen/services/device/public/interfaces/interfaces__type_mappings --use_once_callback
Traceback (most recent call last):
  File "../../mojo/public/tools/bindings/mojom_bindings_generator.py", line 401, in <module>
    sys.exit(main())
  File "../../mojo/public/tools/bindings/mojom_bindings_generator.py", line 397, in main
    return args.func(args, remaining_args)
  File "../../mojo/public/tools/bindings/mojom_bindings_generator.py", line 285, in _Generate
    processor.ProcessFile(args, remaining_args, generator_modules, filename)
  File "../../mojo/public/tools/bindings/mojom_bindings_generator.py", line 174, in ProcessFile
    RelativePath(filename, args.depth))
  File "../../mojo/public/tools/bindings/mojom_bindings_generator.py", line 225, in _GenerateModule
    generator.GenerateFiles(filtered_args)
  File "C:\b\c\b\win\src\mojo\public\tools\bindings\generators\mojom_java_generator.py", line 533, in GenerateFiles
    build_utils.ZipDir(zip_filename, temp_java_root)
  File "C:\b\depot_tools\win_tools-2_7_6_bin\python\bin\lib\contextlib.py", line 24, in __exit__
    self.gen.next()
  File "C:\b\c\b\win\src\mojo\public\tools\bindings\generators\mojom_java_generator.py", line 406, in TempDir
    shutil.rmtree(dirname)
  File "C:\b\depot_tools\win_tools-2_7_6_bin\python\bin\lib\shutil.py", line 247, in rmtree
    rmtree(fullname, ignore_errors, onerror)
  File "C:\b\depot_tools\win_tools-2_7_6_bin\python\bin\lib\shutil.py", line 247, in rmtree
    rmtree(fullname, ignore_errors, onerror)
  File "C:\b\depot_tools\win_tools-2_7_6_bin\python\bin\lib\shutil.py", line 247, in rmtree
    rmtree(fullname, ignore_errors, onerror)
  File "C:\b\depot_tools\win_tools-2_7_6_bin\python\bin\lib\shutil.py", line 256, in rmtree
    onerror(os.rmdir, path, sys.exc_info())
  File "C:\b\depot_tools\win_tools-2_7_6_bin\python\bin\lib\shutil.py", line 254, in rmtree
    os.rmdir(path)
WindowsError: [Error 145] The directory is not empty: 'c:\\users\\chrome~1\\appdata\\local\\temp\\tmpwu9f33\\org\\chromium\\device'

Here's the build URL: https://ci.chromium.org/buildbot/tryserver.chromium.win/win7_chromium_rel_ng/80583
CL: https://chromium-review.googlesource.com/c/chromium/src/+/800615, doesn't touch services/device.

Looks like a flake (tmp directory was reused?), so I'll just retry.