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/actors/process.rs

@@ -2,12 +2,16 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
 
+//! Liberally derived from the [Firefox JS implementation]
+//! (https://searchfox.org/mozilla-central/source/devtools/server/actors/descriptors/process.js)
+
 use std::net::TcpStream;
 
 use serde::Serialize;
 use serde_json::{Map, Value};
 
 use crate::actor::{Actor, ActorMessageStatus, ActorRegistry};
+use crate::actors::root::DescriptorTraits;
 use crate::protocol::JsonPacketStream;
 use crate::StreamId;
 
@@ -17,14 +21,18 @@ struct ListWorkersReply {
     workers: Vec<u32>, // TODO: use proper JSON structure.
 }
 
-pub struct ProcessActor {
-    name: String,
+#[derive(Serialize)]
+#[serde(rename_all = "camelCase")]
+pub struct ProcessActorMsg {
+    actor: String,
+    id: u32,
+    is_parent: bool,
+    is_windowless_parent: bool,
+    traits: DescriptorTraits,
 }
 
-impl ProcessActor {
-    pub fn new(name: String) -> Self {
-        Self { name }
-    }
+pub struct ProcessActor {
+    name: String,
 }
 
 impl Actor for ProcessActor {
@@ -32,6 +40,9 @@ impl Actor for ProcessActor {
         self.name.clone()
     }
 
+    /// The process actor can handle the following messages:
+    ///
+    /// - `listWorkers`: Returns a list of web workers, not supported yet.
     fn handle_message(
         &self,
         _registry: &ActorRegistry,
@@ -54,3 +65,19 @@ impl Actor for ProcessActor {
         })
     }
 }
+
+impl ProcessActor {
+    pub fn new(name: String) -> Self {
+        Self { name }
+    }
+
+    pub fn encodable(&self) -> ProcessActorMsg {
+        ProcessActorMsg {
+            actor: self.name(),
+            id: 0,
+            is_parent: true,
+            is_windowless_parent: false,
+            traits: Default::default(),
+        }
+    }
+}