Replacing the Node EventEmitter with Mitt caused more problems than
anticipated for end users due to the API differences and the amount of
people who relied on the EventEmitter API. In hindsight this clearly
should have been explored more and then released as a breaking v4.
This commit rolls us back to the built in Node EventEmitter library
which we can release to get everyone back on stable builds. We can then
consider our approach to migrating to Mitt and when we do do that we can
release it as a breaking change and properly document the migration
strategy and approach.
* chore: migrate to Mitt as the EventEmitter
This commit moves us to using Mitt [1] for the event emitter in
Puppeteer. This removes our dependency to Node's EventEmitter which is
part of a larger stream of work to enable a Puppeteer-web version that
doesn't depend on Node.
There are no large breaking changes as we support the main methods that
EventEmitter had, but it also provides some methods that Puppeteer
didn't use. Technically end users could depend on this but it's
unlikely.
[1]: https://github.com/developit/mitt
* chore: extract `BrowserRunner` into its own module
`src/Launcher.ts` is large and hard to work in. It has multiple objects
defined in it:
* ChromeLauncher
* FirefoxLauncher
* BrowserRunner
* Launcher
This change moves BrowserRunner into its own module. More refactorings
like this will follow but this is the first step.
