Bug 1564105 - Enable WS Monitor in Nightly. r=Honza,jdescottes

Enable WS Monitor in Nightly

Differential Revision: https://phabricator.services.mozilla.com/D38230

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

devtools/client/preferences/devtools-client.js

@@ -189,8 +189,12 @@ pref("devtools.netmonitor.har.forceExport", false);
 pref("devtools.netmonitor.har.pageLoadedTimeout", 1500);
 pref("devtools.netmonitor.har.enableAutoExportToFile", false);
 
-// Support for WebSocket monitoring pref (pending complete implementation)
+// Enable WebSocket monitoring in Nightly builds.
+#if defined(NIGHTLY_BUILD)
+pref("devtools.netmonitor.features.webSockets", true);
+#else
 pref("devtools.netmonitor.features.webSockets", false);
+#endif
 
 // Scratchpad settings
 // - recentFileMax: The maximum number of recently-opened files

devtools/server/actors/network-monitor/websocket-actor.js

@@ -23,7 +23,7 @@ const WebSocketActor = ActorClassWithSpec(webSocketSpec, {
     Actor.prototype.initialize.call(this, conn);
 
     this.targetActor = targetActor;
-    this.listening = false;
+    this.innerWindowID = null;
 
     // Each connection's webSocketSerialID is mapped to a httpChannelId
     this.connections = new Map();
@@ -54,22 +54,20 @@ const WebSocketActor = ActorClassWithSpec(webSocketSpec, {
   // Actor API
 
   startListening: function() {
-    // Register WS listener
-    if (!this.listening) {
-      const innerWindowID = this.targetActor.window.windowUtils
-        .currentInnerWindowID;
-      webSocketEventService.addListener(innerWindowID, this);
-      this.listening = true;
-    }
+    this.stopListening();
+    this.innerWindowID = this.targetActor.window.windowUtils.currentInnerWindowID;
+    webSocketEventService.addListener(this.innerWindowID, this);
   },
 
   stopListening() {
-    if (this.listening) {
-      const innerWindowID = this.targetActor.window.windowUtils
-        .currentInnerWindowID;
-      webSocketEventService.removeListener(innerWindowID, this);
-      this.listening = false;
+    if (!this.innerWindowID) {
+      return;
     }
+    if (webSocketEventService.hasListenerFor(this.innerWindowID)) {
+      webSocketEventService.removeListener(this.innerWindowID, this);
+    }
+
+    this.innerWindowID = null;
   },
 
   // nsIWebSocketEventService

devtools/shared/fronts/websocket.js

@@ -37,9 +37,6 @@ class WebSocketFront extends FrontClassWithSpec(webSocketSpec) {
    *
    */
   destroy() {
-    if (!this._client) {
-      return null;
-    }
     this.off("serverWebSocketOpened");
     this.off("serverWebSocketClosed");
     this.off("serverFrameSent");