[DevTools] Refactor connection-related classes.

third_party/WebKit/Source/devtools/front_end/audits2/Audits2Panel.js

 // Copyright (c) 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 /**
  * @constructor
  * @extends {WebInspector.Panel}
  */
 WebInspector.Audits2Panel = function()
 {
     WebInspector.Panel.call(this, "audits2");
     this.contentElement.classList.add("vbox");
     this.contentElement.appendChild(createTextButton(WebInspector.UIString("Start"), this._start.bind(this)));
     this.contentElement.appendChild(createTextButton(WebInspector.UIString("Stop"), this._stop.bind(this)));
 }
 
 WebInspector.Audits2Panel.prototype = {
     _start: function()
     {
-        WebInspector.targetManager.interceptMainConnection(this._dispatchProtocolMessage.bind(this)).then(rawConnection => {
-            this._rawConnection = rawConnection;
+        WebInspector.targetManager.mainChannelInterceptor().takeMainChannel().then(channel => {
+            this._channel = channel;
+            this._channel.addEventListener(InspectorBackendClass.Channel.Events.MessageReceived, this._dispatchProtocolMessage, this);

[pfeldman, 2016/10/21 21:04:34]

design: You don't want to expose the MessageReceived as an event API, it needs
to be private to the handler as it was previously.

             this._send("start");
         });
     },
 
     /**
-     * @param {string} message
+     * @param {!WebInspector.Event} event
      */
-    _dispatchProtocolMessage: function(message)
+    _dispatchProtocolMessage: function(event)
     {
+        var message = /** @type {!Object|string} */ (event.data);
         this._send("dispatchProtocolMessage", {message: message});
     },
 
     _stop: function()
     {
         this._send("stop").then(() => {
-            this._rawConnection.yieldConnection();
+            this._channel.removeEventListener(InspectorBackendClass.Channel.Events.MessageReceived, this._dispatchProtocolMessage, this);
             this._backend.dispose();
+            delete this._channel;
             delete this._backend;
             delete this._backendPromise;
+            WebInspector.targetManager.mainChannelInterceptor().yieldMainChannel();

[pfeldman, 2016/10/21 21:04:33]

design: only the one how has connection should be able to yield it.

         });
     },
 
     /**
      * @param {string} method
      * @param {!Object=} params
      * @return {!Promise<!Object|undefined>}
      */
     _send: function(method, params)
     {
         if (!this._backendPromise) {
             this._backendPromise = WebInspector.serviceManager.createAppService("audits2_worker", "Audits2Service", false).then(backend => {
                 this._backend = backend;
-                this._backend.on("sendProtocolMessage", result => this._rawConnection.send(result.message));
+                this._backend.on("sendProtocolMessage", result => this._channel.sendMessage(result.message));
             });
         }
         return this._backendPromise.then(() => this._backend ? this._backend.send(method, params) : undefined);
     },
 
     __proto__: WebInspector.Panel.prototype
 }