This patch serves as documentation for adding a single brower-based perftest to the accessibility perftesting suite.
Some things to note:
- Your additional test should be disabled in the `perftest.toml` file to avoid it running by any framework that slurps up `*.toml` files from `/accessible/browser/` subdirectories. It will still run under the `./mach perftest` command and in the associated `./mach try perf` job, if added to CI.
- Please verify your test runs via `./mach test` or `./mach mochitest` without errors before running with `./mach perftest`.
- You'll need to copy the `perfMetadata` object from an existing test, please modify only the test description and name.
- You'll need to add your test to `config.yml`
- Generate `mozperftest.rst` via `./mach lint -l perfdocs --outgoing --fix`, CI will warn you about this if you fail to do it.
- We cannot currently run perftest manifests in CI, each test needs to be added individually. Keep in mind that the firefox binary file location is different per platform; you can copy/paste from the existing test configs to set up your new test, but do not copy (for example) from `linux.yml` to `macos.yml`.
- Our timer function (`timeThis`) can only be called once per test. Also, we can only have one test per file.
Differential Revision: https://phabricator.services.mozilla.com/D258639