Simplify NetworkManager's request/response management

This patch:
- drops Request dependency on NetworkManager
- drops Response dependency on NetworkManager
- drops requestIds from Request and Response objects

lib/NetworkManager.js

@@ -26,8 +26,6 @@ class NetworkManager extends EventEmitter {
     this._requestInterceptor = null;
     /* @type {!Map<string, !Request>} */
     this._idToRequest = new Map();
-    /* @type {!Map<string, !Response>} */
-    this._idToResponse = new Map();
     this._httpHeaders = {};
     this._userAgent = userAgent;
 
@@ -94,7 +92,7 @@ class NetworkManager extends EventEmitter {
    * @param {!Object} event
    */
   _onRequestWillBeSent(event) {
-    let request = new Request(this, event.requestId, event.request);
+    let request = new Request(event.request);
     this._idToRequest.set(event.requestId, request);
     this.emit(NetworkManager.Events.Request, request);
   }
@@ -111,8 +109,9 @@ class NetworkManager extends EventEmitter {
    * @param {!Object} event
    */
   _onResponseReceived(event) {
-    let response = new Response(this, event.requestId, event.response);
-    this._idToResponse.set(event.requestId, response);
+    let request = this._idToRequest.get(event.requestId) || null;
+    let response = new Response(request, event.response);
+    request._response = response;
     this.emit(NetworkManager.Events.Response, response);
   }
 
@@ -121,6 +120,7 @@ class NetworkManager extends EventEmitter {
    */
   _onLoadingFinished(event) {
     let request = this._idToRequest.get(event.requestId);
+    this._idToRequest.delete(event.requestId);
     this.emit(NetworkManager.Events.RequestFinished, request);
   }
 
@@ -129,6 +129,7 @@ class NetworkManager extends EventEmitter {
    */
   _onLoadingFailed(event) {
     let request = this._idToRequest.get(event.requestId);
+    this._idToRequest.delete(event.requestId);
     this.emit(NetworkManager.Events.RequestFailed, request);
   }
 }
@@ -220,13 +221,10 @@ class Headers {
 
 class Request {
   /**
-   * @param {!NetworkManager} networkManager
-   * @param {string} id
    * @param {!Object} payload
    */
-  constructor(networkManager, id, payload) {
-    this._networkManager = networkManager;
-    this._id = id;
+  constructor(payload) {
+    this._response = null;
     this.url = payload.url;
     this.method = payload.method;
     this.headers = Headers.fromPayload(payload.headers);
@@ -237,20 +235,17 @@ class Request {
    * @return {?Response}
    */
   response() {
-    return this._networkManager._idToResponse.get(this._id) || null;
+    return this._response;
   }
 }
 
 class Response {
   /**
-   * @param {!NetworkManager} networkManager
-   * @param {string} id
+   * @param {?Request} request
    * @param {!Object} payload
    */
-  constructor(networkManager, id, payload) {
-    this._networkManager = networkManager;
-    this._id = id;
-
+  constructor(request, payload) {
+    this._request = request;
     this.headers = Headers.fromPayload(payload.headers);
     this.ok = payload.status >= 200 && payload.status <= 299;
     this.status = payload.status;
@@ -262,7 +257,7 @@ class Response {
    * @return {?Response}
    */
   request() {
-    return this._networkManager._idToRequest.get(this._id) || null;
+    return this._request;
   }
 }