Bug 1485676 - Prevent exceptions in the emulation actor when trying to use it while it is already destroyed. r=yulia

Summary: Depends On D4540

Reviewers: yulia!

Tags: #secure-revision

Bug #: 1485676

Differential Revision: https://phabricator.services.mozilla.com/D4541

MozReview-Commit-ID: 2fTZ4WRq9je

devtools/server/actors/emulation.js

@@ -48,7 +48,7 @@ const EmulationActor = protocol.ActorClassWithSpec(emulationSpec, {
    * monitor, which for historical reasons is part of the console actor.
    */
   get _consoleActor() {
-    if (this.targetActor.exited) {
+    if (this.targetActor.exited || !this.targetActor.actorID) {
       return null;
     }
     const form = this.targetActor.form();