Bug 1583749 - Remove unnecessary trait webExtensionAddonConnect r=ochameau

Depends on D47050. Trait was added in 2017, all servers should now have support this by default

Differential Revision: https://phabricator.services.mozilla.com/D47051

--HG--
extra : moz-landing-system : lando

devtools/server/actors/root.js

@@ -168,9 +168,6 @@ RootActor.prototype = {
     // Whether or not the timeline actor can emit DOMContentLoaded and Load
     // markers, currently in use by the network monitor. Fx45+
     documentLoadingMarkers: true,
-    // Whether or not the webextension addon actor have to be connected
-    // to retrieve the extension child process target actors.
-    webExtensionAddonConnect: true,
     // Version of perf actor. Fx65+
     // Version 1 - Firefox 65: Introduces a duration-based buffer. It can be controlled
     // by adding a `duration` property (in seconds) to the options passed to

devtools/shared/fronts/descriptors/webextension.js

@@ -56,10 +56,7 @@ class WebExtensionDescriptorFront extends FrontClassWithSpec(
    * the final target actor to use.
    */
   async getTarget() {
-    if (
-      this.isWebExtension &&
-      this.client.mainRoot.traits.webExtensionAddonConnect
-    ) {
+    if (this.isWebExtension) {
       // The Webextension form is related to a WebExtensionActor instance,
       // which isn't a target actor on its own, it is an actor living in the parent
       // process with access to the extension metadata, it can control the extension (e.g.