DevTools server callbacks can outlive the server when deferred work is
queued during connection shutdown. Capture weak pointers for those tasks
and clear socket callbacks while the server is being destroyed so later
actor cleanup cannot touch freed state.
Add protocol coverage that destroys a server with deferred actor cleanup
pending, before adding the style-rule actor path that depends on this.
Firefox creates a new custom highlighter actor for each
getHighlighterByType request. Its frontend decides when to cache and
reuse those actors, while grid highlighting uses distinct actors so
multiple grids and subgrid parent overlays can remain visible at the
same time.
Match that allocation model by removing InspectorActor's server-side
highlighter cache. Also unregister highlighter actors after release or
finalize, and make each actor clear only the highlight state it owns.
This is to prepare for an upcoming change where we will need to track
replies to messages by ID. We will be able to add parameters to this
structure without having to edit every single actor subclass header
file.
The DevTools client will now send requests to the node actor, rather
than just sending messages to other actors on the node's behalf.
This exposed a slight issue in the way we assign actor IDs. Node actors
are created in the walker actor constructor, which executes before the
actor ID is incremented. So we must be sure to increment the actor ID
before invoking any actor constructors. Otherwise, the walker actor and
the first node actor have the same numeric ID.
Previously, we could connect to our DevTools server from Firefox, but
could not see any information on Ladybird's opened tabs. This implements
enough of the protocol to see a tab list, but we cannot yet inspect the
tabs.
To aid with debugging web page issues in Ladybird without needing to
implement a fully fledged inspector, we can implement the Firefox
DevTools protocol and use their DevTools. The protocol is described
here:
https://firefox-source-docs.mozilla.org/devtools/backend/protocol.html
This commit contains just enough to connect to Ladybird from a DevTools
client.
