diff -r 000000000000 -r 6474c204b198 toolkit/devtools/server/child.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/toolkit/devtools/server/child.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,56 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+"use strict";
+
+let chromeGlobal = this;
+
+// Encapsulate in its own scope to allows loading this frame script
+// more than once.
+(function () {
+  let Cu = Components.utils;
+  let { devtools } = Cu.import("resource://gre/modules/devtools/Loader.jsm", {});
+  const DevToolsUtils = devtools.require("devtools/toolkit/DevToolsUtils.js");
+  const {DebuggerServer, ActorPool} = Cu.import("resource://gre/modules/devtools/dbg-server.jsm", {});
+
+  if (!DebuggerServer.initialized) {
+    DebuggerServer.init();
+  }
+
+  // In case of apps being loaded in parent process, DebuggerServer is already
+  // initialized, but child specific actors are not registered.
+  // Otherwise, for apps in child process, we need to load actors the first
+  // time we load child.js
+  DebuggerServer.addChildActors();
+
+  let conn;
+
+  let onConnect = DevToolsUtils.makeInfallible(function (msg) {
+    removeMessageListener("debug:connect", onConnect);
+
+    let mm = msg.target;
+
+    conn = DebuggerServer.connectToParent(msg.data.prefix, mm);
+
+    let actor = new DebuggerServer.ContentActor(conn, chromeGlobal);
+    let actorPool = new ActorPool(conn);
+    actorPool.addActor(actor);
+    conn.addActorPool(actorPool);
+
+    sendAsyncMessage("debug:actor", {actor: actor.grip()});
+  });
+
+  addMessageListener("debug:connect", onConnect);
+
+  let onDisconnect = DevToolsUtils.makeInfallible(function (msg) {
+    removeMessageListener("debug:disconnect", onDisconnect);
+
+    // Call DebuggerServerConnection.close to destroy all child actors
+    // (It should end up calling DebuggerServerConnection.onClosed
+    // that would actually cleanup all actor pools)
+    conn.close();
+    conn = null;
+  });
+  addMessageListener("debug:disconnect", onDisconnect);
+})();