headless-browser currently uses its own PageClient to load web pages
in-process. Due to this, it also needs to set up a whole bunch of other
objects needed to run LibWeb, e.g. image decoders, request servers, etc.
This changes headless-browser to instead implement a WebView to launch
WebContent out-of-process. This implementation is almost entirely empty,
but can be filled in as-needed. For example, we may want to print
JavaScript console messages.
This allows the WebDriver to take advantage of the common helper process
spawning code when launching ladybird, and to not assume a particular
directory layout.
This allows us to use standard Serenity IPC infrastructure rather than
manually creating FD-passing sockets. This also lets us use Serenity's
WebDriver Session class, removing the copy previously used in Ladybird.
This ensures any changes to Session in the future will be picked up by
Ladybird for free.
This adds a WebDriver binary for Ladybird to make use of Serenity's
WebDriver implementation. This has to use the same IPC socket handling
that was used to make WebContent work out-of-process. Besides that, we
are able to reuse almost everything from Serenity.
