Since ChromeDriver v2.41, ChromeDriver will only connect if, either we precise a port
for remote debugging, either the embedder (ie electron) made sure to pass `USER_DATA_DIR`
to the remote debugging server.
So, for now, we'll just use a random port (we don't care about its value since we're not
connecting through it).
(inspired by 737db138bd).
Previously, we used to save the window's state in the renderer process
`beforeunload` event handler: because of the synchronous nature of event
handlers and the asynchronous design of IndexedDB, this could
potentially not save anything if windows close fast enough to prevent
IndexedDB from committing the pending transaction containing the state.
(Ref.: https://mzl.la/2bXCXDn)
With this commit, we will intercept the `before-quit` events on
`electron.app` and the `close` event on `BrowserWindow` (which will fire
respectively before quitting the application and before closing a
window), and prevent them from performing the default action. We will
then ask each renderer process to save its state and, finally, close the
window and/or the app.
Unless a choice has been made by the user, this tab always shows up as
the first one when opening Atom, thus breaking some of the assumptions
we make in the main process tests.
It was testing something that didn’t actually work, that opening a
directory that was already open in an existing window would recycle the
window. We explicitly don’t behave that way and the old test was passing
spuriously.
