DevTools: Implement watcher actor (#32509)

* feat: base for watcher

* feat: some more watcher tests

* feat: implement getWatcher

* refactor: clean up getWatcher

* feat: implement watchTargets

* feat: implement watchResources

* feat: very messy watchTargets fix

* refactor: clean browsing context

* feat: target configuration

* refactor: start cleanup

* refactor: more doc coments

* refactor: clean browsing context

components/devtools/lib.rs

@@ -5,7 +5,7 @@
 //! An actor-based remote devtools server implementation. Only tested with
 //! nightly Firefox versions at time of writing. Largely based on
 //! reverse-engineering of Firefox chrome devtool logs and reading of
-//! [code](http://mxr.mozilla.org/mozilla-central/source/toolkit/devtools/server/).
+//! [code](https://searchfox.org/mozilla-central/source/devtools/server).
 
 #![crate_name = "devtools"]
 #![crate_type = "rlib"]
@@ -48,9 +48,10 @@ use crate::actors::worker::{WorkerActor, WorkerType};
 use crate::protocol::JsonPacketStream;
 
 mod actor;
-/// Corresponds to <http://mxr.mozilla.org/mozilla-central/source/toolkit/devtools/server/actors/>
+/// <https://searchfox.org/mozilla-central/source/devtools/server/actors>
 mod actors {
     pub mod browsing_context;
+    pub mod configuration;
     pub mod console;
     pub mod device;
     pub mod emulation;
@@ -68,6 +69,7 @@ mod actors {
     pub mod tab;
     pub mod thread;
     pub mod timeline;
+    pub mod watcher;
     pub mod worker;
 }
 mod protocol;
@@ -113,6 +115,11 @@ struct ResponseStartUpdateMsg {
     response: ResponseStartMsg,
 }
 
+#[derive(Serialize)]
+pub struct EmptyReplyMsg {
+    pub from: String,
+}
+
 /// Spin up a devtools server that listens for connections on the specified port.
 pub fn start_server(port: u16, embedder: EmbedderProxy) -> Sender<DevtoolsControlMsg> {
     let (sender, receiver) = unbounded();