chromium/tools/mb/mb_config_expectations/official.chrome.json

{
  "fuchsia-arm64": {
    "args_file": "//build/custom_args.gn",
    "gn_args": {
      "is_chrome_branded": true,
      "is_official_build": true,
      "target_cpu": "arm64",
      "target_os": "fuchsia",
      "test_host_cpu": "arm64"
    }
  },
  "fuchsia-x64": {
    "args_file": "//build/custom_args.gn",
    "gn_args": {
      "is_chrome_branded": true,
      "is_official_build": true,
      "target_cpu": "x64",
      "target_os": "fuchsia"
    }
  }
}