We currently create a separate headless-browser application to serve two
purposes:
1. Allow headless browsing to take a screenshot of a page or print its
layout tree / internal text.
2. Run the LibWeb test framework.
This patch migrates (1) to the main Ladybird executable. The --headless
flag enables this mode. This matches the behavior of other browsers, and
means we have one less executable to ship at distribution time.
We want to avoid creating too many AppKit / Qt facilities in headless
mode. So this involves some shuffling of application init to ensure we
don't create them until after we've parsed the command line arguments.
Namely, we avoid creating the NSApp in AppKit and QCoreApplication in
Qt. Doing so also requires that we don't create the application event
loop until we've parsed the command line as well, because the loop we
create depends on whether we're creating those UI facilities.
Since cross-site navigation is a pretty frequent task, creating a spare
process is commonplace in other browsers to reduce the overhead of
directing the target site to a new process.
We store this process on the WebView application. If it is unavailable,
we queue a task to create it later.
Our existing WebContentConsoleClient is very specific to our home-grown
Inspector. It renders console output to an HTML string. For DevTools, we
will not want this behavior; we will want to send representations of raw
JS values.
This patch makes WebContentConsoleClient a base class to handle console
input from the user, either from the Inspector or from DevTools. It then
moves the HTML rendering needed for the Inspector to a new class,
InspectorConsoleClient. And we add a DevToolsConsoleClient (currently
just stubbed) to handle needs specific to DevTools.
We choose at runtime which console client to install, based on the
--devtools command line flag.
LibWebView now knows how to launch RequestServer and ImageDecoderServer
without help from the UI, so let's move ownership of these services over
to LibWebView for de-duplication.
