Bug 1019964 - CallWatcherActor no longer holds strong references in FunctionCallActor. r=vp

toolkit/devtools/server/actors/call-watcher.js

@@ -73,15 +73,27 @@ let FunctionCallActor = protocol.ActorClass({
     protocol.Actor.prototype.initialize.call(this, conn);
 
     this.details = {
-      window: window,
-      caller: caller,
       type: type,
       name: name,
       stack: stack,
-      args: args,
-      result: result
     };
 
+    // Store a weak reference to all objects so we don't
+    // prevent natural GC.
+    let weakRefs = {
+      window: Cu.getWeakReference(window),
+      caller: Cu.getWeakReference(caller),
+      result: Cu.getWeakReference(result),
+      args: Cu.getWeakReference(args)
+    };
+
+    Object.defineProperties(this.details, {
+      window: { get: () => weakRefs.window.get() },
+      caller: { get: () => weakRefs.caller.get() },
+      result: { get: () => weakRefs.result.get() },
+      args: { get: () => weakRefs.args.get() }
+    });
+
     this.meta = {
       global: -1,
       previews: { caller: "", args: "" }