This supports evaluating the script and replying with the result. We
currently serialize JS objects to a string, but we will need to support
dynamic interaction with the objects over IPC. This does not yet support
sending console messages to DevTools.
This adds a command line option to enable the DevTools server. Here, we
make the application the DevToolsDelegate to reply to requests from the
DevTools server about the state of the application.
This commit adds a "echo_server_port" property to `WebContentOptions`.
Additionally, it makes `Application::web_content_options()` return a
mutable reference instead of a const reference so that we can set the
port value from the fixture.
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.
