Issue #2494 - Use correct optional chaining operator.

Resolves #2494

devtools/client/webconsole/console-output.js

@@ -249,6 +249,39 @@ ConsoleOutput.prototype = {
     return message.render().element;
   },
 
+  /**
+   * Clear the netRequests Map in this.owner.window.
+   * Items of NetRequest() in chrome/devtools/modules/devtools/client/webconsole/net/net-request.js
+   * netRequest.file holds response
+   * netRequest.parentNode holds div above bodyWrapper here in console-output.js
+   */
+  onConsoleClear: function() {
+    let netRequests = this.owner.?window.?netRequests;
+    let toClear = [];
+    if(netRequests && netRequests.forEach){
+      // Build list of items to clear
+      netRequests.forEach(
+        function(netReq,key){
+          if (netReq.parentNode && !netReq.parentNode.parentNode) {
+            // DOM node was removed from the browser console output, but still referenced...
+            toClear.push({netReq:netReq,
+                          key:key});
+          }
+        });
+      // ... and clean them up
+      toClear.forEach(
+        function(item){
+          let netReq = item.netReq, key = item.key;
+          let file = netReq.file || {};
+          netReq.parentNode = file.node = null;
+          file.request = file.response = file.cause = file.updates = null;
+          netReq.client = netReq.owner = netReq.file = null;
+          item.netReq = null;
+          netRequests.delete(key);
+        });
+    }
+  },
+
   /**
    * Get an array of selected messages. This list is based on the text selection
    * start and end points.

devtools/client/webconsole/jsterm.js

@@ -960,6 +960,10 @@ JSTerm.prototype = {
       hud.newConsoleOutput.dispatchMessagesClear();
     }
 
+    if(hud.output && hud.output.onConsoleClear) {
+      hud.output.onConsoleClear();
+    }
+
     this.emit("messages-cleared");
   },
 

devtools/server/actors/webconsole.js

@@ -309,7 +309,7 @@ WebConsoleActor.prototype =
   actorPrefix: "console",
 
   get globalDebugObject() {
-    return this.parentActor.threadActor.globalDebugObject;
+    return this.parentActor?.threadActor?.globalDebugObject;
   },
 
   grip: function WCA_grip()
@@ -1071,6 +1071,42 @@ WebConsoleActor.prototype =
       ConsoleAPIStorage.clearEvents(aId);
     });
 
+    if (this._actorPool && this.networkMonitor) {
+      // Clear NetworkEventActor items from its NetworkMonitor
+      let actor, aid, n;
+      let allActors = this._actorPool._actors;
+      let voidActor = {actorID:0,
+                       release:function(){},
+                       stub:true};
+
+      // Build list of NetworkEventActors
+      let netActors = [];
+      for (n in allActors)  {
+        if (n.indexOf('netEvent')>=0) {
+          netActors.push(allActors[n]);
+        }
+      }
+      // ... and release them.
+      for (actor of netActors) {
+        if(actor) {
+          if (actor.release) {
+            actor.release();
+          }
+        }
+      }
+      // XXX: Sometimes the actors are not removed upon calling release() (async?)
+      // Force the issue by unlinking the actor from active scripting and deleting.
+      for (actor of netActors) {
+        if(actor) {
+          aid = actor.actorID;
+          if (aid && allActors[aid]) {
+            allActors[aid] = voidActor;
+            delete allActors[aid];
+          }
+        }
+      }
+    }
+    
     if (this.parentActor.isRootActor) {
       Services.console.logStringMessage(null); // for the Error Console
       Services.console.reset();