Dummy handler for getAvailableEventBreakpoints in thread actor

Co-authored-by: atbrakhi <atbrakhi@igalia.com>
Signed-off-by: Delan Azabani <dazabani@igalia.com>

components/devtools/actors/thread.rs

@@ -91,6 +91,12 @@ pub enum Location {
     },
 }
 
+#[derive(Serialize)]
+struct GetAvailableEventBreakpointsReply {
+    from: String,
+    value: Vec<()>,
+}
+
 impl Actor for ThreadActor {
     fn name(&self) -> String {
         self.name.clone()
@@ -152,6 +158,17 @@ impl Actor for ThreadActor {
                 };
                 request.reply_final(&msg)?
             },
+
+            // Client wants to know what Event Listener Breakpoints are available for this thread.
+            "getAvailableEventBreakpoints" => {
+                let msg = GetAvailableEventBreakpointsReply {
+                    from: self.name(),
+                    // TODO: populate this.
+                    value: vec![],
+                };
+                request.reply_final(&msg)?
+            },
+
             _ => return Err(ActorError::UnrecognizedPacketType),
         };
         Ok(())