Updated remoting.xhr API to use promises.

Removed access to the native XHR object used by the API.

This is a larger change than one might expect for two reasons: First,
because the native XHR object only allows the response content to be
retrieved while the onreadystatechange handler is executing, and
second, because the unit test for dns_blackhole_checker.js relied on
synchronous semantics which cannot be duplicated with promises because
when a promise is resolved, its "then" handlers are not called until
the next event cycle.

Review URL: https://codereview.chromium.org/1003433002

Cr-Commit-Position: refs/heads/master@{#321608}

remoting/webapp/app_remoting/js/app_remoting.js

@@ -105,11 +105,11 @@ remoting.AppRemoting.prototype.start = function(connector, token) {
   /** @type {remoting.AppRemoting} */
   var that = this;
 
-  /** @param {XMLHttpRequest} xhr */
-  var parseAppHostResponse = function(xhr) {
-    if (xhr.status == 200) {
+  /** @param {!remoting.Xhr.Response} xhrResponse */
+  var parseAppHostResponse = function(xhrResponse) {
+    if (xhrResponse.status == 200) {
       var response = /** @type {remoting.AppRemoting.AppHostResponse} */
-          (base.jsonParseSafe(xhr.responseText));
+          (base.jsonParseSafe(xhrResponse.getText()));
       if (response &&
           response.status &&
           response.status == 'done' &&
@@ -157,16 +157,16 @@ remoting.AppRemoting.prototype.start = function(connector, token) {
       // TODO(garykac) Start using remoting.Error.fromHttpStatus once it has
       // been updated to properly report 'unknown' errors (rather than
       // reporting them as AUTHENTICATION_FAILED).
-      if (xhr.status == 0) {
+      if (xhrResponse.status == 0) {
         that.handleError(new remoting.Error(
             remoting.Error.Tag.NETWORK_FAILURE));
-      } else if (xhr.status == 401) {
+      } else if (xhrResponse.status == 401) {
         that.handleError(new remoting.Error(
             remoting.Error.Tag.AUTHENTICATION_FAILED));
-      } else if (xhr.status == 403) {
+      } else if (xhrResponse.status == 403) {
         that.handleError(new remoting.Error(
             remoting.Error.Tag.APP_NOT_AUTHORIZED));
-      } else if (xhr.status == 502 || xhr.status == 503) {
+      } else if (xhrResponse.status == 502 || xhrResponse.status == 503) {
         that.handleError(new remoting.Error(
             remoting.Error.Tag.SERVICE_UNAVAILABLE));
       } else {
@@ -175,12 +175,11 @@ remoting.AppRemoting.prototype.start = function(connector, token) {
     }
   };
 
-  remoting.xhr.start({
+  new remoting.Xhr({
     method: 'POST',
     url: that.runApplicationUrl(),
-    onDone: parseAppHostResponse,
     oauthToken: token
-  });
+  }).start().then(parseAppHostResponse);
 };
 
 /**

remoting/webapp/app_remoting/js/feedback_consent.js

@@ -127,21 +127,19 @@ function onToken(token) {
           '/applications/' + remoting.settings.getAppRemotingApplicationId() +
           '/hosts/'  + hostId +
           '/reportIssue';
-      /** @param {XMLHttpRequest} xhr */
-      var onDone = function(xhr) {
-        if (xhr.status >= 200 && xhr.status < 300) {
+      var onDone = function(/** !remoting.Xhr.Response */ response) {
+        if (response.status >= 200 && response.status < 300) {
           getUserInfo();
         } else {
           showError();
         }
       };
-      remoting.xhr.start({
+      new remoting.Xhr({
         method: 'POST',
         url: uri,
-        onDone: onDone,
         jsonContent: body,
         oauthToken: token
-      });
+      }).start().then(onDone);
     } else {
       getUserInfo();
     }

remoting/webapp/crd/js/dns_blackhole_checker.js

@@ -38,7 +38,7 @@ remoting.DnsBlackholeChecker = function(signalStrategy) {
   /** @private */
   this.blackholeState_ = BlackholeState.PENDING;
 
-  /** @private {?XMLHttpRequest} */
+  /** @private {?remoting.Xhr} */
   this.xhr_ = null;
 };
 
@@ -85,11 +85,11 @@ remoting.DnsBlackholeChecker.prototype.connect = function(server,
 
   this.signalStrategy_.connect(server, username, authToken);
 
-  this.xhr_ = remoting.xhr.start({
+  this.xhr_ = new remoting.Xhr({
     method: 'GET',
-    url: remoting.DnsBlackholeChecker.URL_TO_REQUEST_,
-    onDone: this.onHttpRequestDone_.bind(this)
+    url: remoting.DnsBlackholeChecker.URL_TO_REQUEST_
   });
+  this.xhr_.start().then(this.onHttpRequestDone_.bind(this));
 };
 
 remoting.DnsBlackholeChecker.prototype.getState = function() {
@@ -153,12 +153,12 @@ remoting.DnsBlackholeChecker.prototype.onWrappedSignalStrategyStateChanged_ =
 };
 
 /**
- * @param {XMLHttpRequest} xhr
+ * @param {!remoting.Xhr.Response} response
  * @private
  */
-remoting.DnsBlackholeChecker.prototype.onHttpRequestDone_ = function(xhr) {
+remoting.DnsBlackholeChecker.prototype.onHttpRequestDone_ = function(response) {
   this.xhr_ = null;
-  if (xhr.status >= 200 && xhr.status <= 299) {
+  if (response.status >= 200 && response.status <= 299) {
     console.log("DNS blackhole check succeeded.");
     this.blackholeState_ = BlackholeState.OPEN;
     if (this.signalStrategy_.getState() ==
@@ -166,14 +166,15 @@ remoting.DnsBlackholeChecker.prototype.onHttpRequestDone_ = function(xhr) {
       this.setState_(remoting.SignalStrategy.State.CONNECTED);
     }
   } else {
-    console.error("DNS blackhole check failed: " + xhr.status + " " +
-                  xhr.statusText + ". Response URL: " + xhr.responseURL +
-                  ". Response Text: " + xhr.responseText);
+    console.error("DNS blackhole check failed: " + response.status + " " +
+                  response.statusText + ". Response URL: " +
+                  response.url + ". Response Text: " +
+                  response.getText());
     this.blackholeState_ = BlackholeState.BLOCKED;
     base.dispose(this.signalStrategy_);
     this.setState_(remoting.SignalStrategy.State.FAILED);
   }
-}
+};
 
 /**
  * @param {remoting.SignalStrategy.State} newState

remoting/webapp/crd/js/dns_blackhole_checker_unittest.js

@@ -23,13 +23,15 @@ var checker = null;
 
 /** @type {remoting.MockSignalStrategy} */
 var signalStrategy = null;
-var fakeXhrs;
+
+/** @type {sinon.FakeXhr} */
+var fakeXhr = null;
 
 QUnit.module('dns_blackhole_checker', {
   beforeEach: function(assert) {
-    fakeXhrs = [];
     sinon.useFakeXMLHttpRequest().onCreate = function(xhr) {
-      fakeXhrs.push(xhr);
+      QUnit.equal(fakeXhr, null, 'exactly one XHR is issued');
+      fakeXhr = xhr;
     };
 
     onStateChange = sinon.spy();
@@ -46,9 +48,8 @@ QUnit.module('dns_blackhole_checker', {
     sinon.assert.calledWith(signalStrategy.connect, 'server', 'username',
                             'authToken');
 
-    assert.equal(fakeXhrs.length, 1, 'exactly one XHR is issued');
     assert.equal(
-        fakeXhrs[0].url, remoting.DnsBlackholeChecker.URL_TO_REQUEST_,
+        fakeXhr.url, remoting.DnsBlackholeChecker.URL_TO_REQUEST_,
         'the correct URL is requested');
   },
   afterEach: function() {
@@ -59,112 +60,136 @@ QUnit.module('dns_blackhole_checker', {
     onStateChange = null;
     onIncomingStanzaCallback = null;
     checker = null;
-  },
+    fakeXhr = null;
+  }
 });
 
 QUnit.test('success',
   function(assert) {
-    fakeXhrs[0].respond(200);
-    sinon.assert.notCalled(onStateChange);
-
-    [
-      remoting.SignalStrategy.State.CONNECTING,
-      remoting.SignalStrategy.State.HANDSHAKE,
-      remoting.SignalStrategy.State.CONNECTED
-    ].forEach(function(state) {
+    function checkState(state) {
       signalStrategy.setStateForTesting(state);
       sinon.assert.calledWith(onStateChange, state);
       assert.equal(checker.getState(), state);
+    }
+
+    return base.SpyPromise.run(function() {
+      fakeXhr.respond(200);
+    }).then(function() {
+      sinon.assert.notCalled(onStateChange);
+      checkState(remoting.SignalStrategy.State.CONNECTING);
+      checkState(remoting.SignalStrategy.State.HANDSHAKE);
+      checkState(remoting.SignalStrategy.State.CONNECTED);
     });
-  }
-);
+  });
 
 QUnit.test('http response after connected',
   function(assert) {
-    [
-      remoting.SignalStrategy.State.CONNECTING,
-      remoting.SignalStrategy.State.HANDSHAKE,
-    ].forEach(function(state) {
+    function checkState(state) {
       signalStrategy.setStateForTesting(state);
       sinon.assert.calledWith(onStateChange, state);
       assert.equal(checker.getState(), state);
-    });
+    }
+
+    checkState(remoting.SignalStrategy.State.CONNECTING);
+    checkState(remoting.SignalStrategy.State.HANDSHAKE);
     onStateChange.reset();
 
     // Verify that DnsBlackholeChecker stays in HANDSHAKE state even if the
     // signal strategy has connected.
-    signalStrategy.setStateForTesting(remoting.SignalStrategy.State.CONNECTED);
-    sinon.assert.notCalled(onStateChange);
+    return base.SpyPromise.run(function() {
+      signalStrategy.setStateForTesting(
+          remoting.SignalStrategy.State.CONNECTED);
+    }).then(function() {
+      sinon.assert.notCalled(onStateChange);
     assert.equal(checker.getState(), remoting.SignalStrategy.State.HANDSHAKE);
 
-    // Verify that DnsBlackholeChecker goes to CONNECTED state after the
-    // the HTTP request has succeeded.
-    fakeXhrs[0].respond(200);
-    sinon.assert.calledWith(onStateChange,
-                            remoting.SignalStrategy.State.CONNECTED);
-  }
-);
+      // Verify that DnsBlackholeChecker goes to CONNECTED state after the
+      // the HTTP request has succeeded.
+      return base.SpyPromise.run(function() {
+        fakeXhr.respond(200);
+      });
+    }).then(function() {
+      sinon.assert.calledWith(onStateChange,
+                              remoting.SignalStrategy.State.CONNECTED);
+    });
+  });
 
 QUnit.test('connect failed',
   function(assert) {
-    fakeXhrs[0].respond(200);
-    sinon.assert.notCalled(onStateChange);
-
-    [
-      remoting.SignalStrategy.State.CONNECTING,
-      remoting.SignalStrategy.State.FAILED
-    ].forEach(function(state) {
+    function checkState(state) {
       signalStrategy.setStateForTesting(state);
       sinon.assert.calledWith(onStateChange, state);
+    };
+
+    return base.SpyPromise.run(function() {
+      fakeXhr.respond(200);
+    }).then(function() {
+      sinon.assert.notCalled(onStateChange);
+      checkState(remoting.SignalStrategy.State.CONNECTING);
+      checkState(remoting.SignalStrategy.State.FAILED);
     });
-}
-);
+  });
 
 QUnit.test('blocked',
   function(assert) {
-    fakeXhrs[0].respond(400);
-    sinon.assert.calledWith(onStateChange,
-                            remoting.SignalStrategy.State.FAILED);
+    function checkState(state) {
     assert.equal(checker.getError().getTag(),
                  remoting.Error.Tag.NOT_AUTHORIZED);
-    onStateChange.reset();
-
-    [
-      remoting.SignalStrategy.State.CONNECTING,
-      remoting.SignalStrategy.State.HANDSHAKE,
-      remoting.SignalStrategy.State.CONNECTED
-    ].forEach(function(state) {
+      onStateChange.reset();
       signalStrategy.setStateForTesting(state);
       sinon.assert.notCalled(onStateChange);
-      assert.equal(checker.getState(), remoting.SignalStrategy.State.FAILED);
+      assert.equal(checker.getState(),
+          checker.getState(),
+          remoting.SignalStrategy.State.FAILED,
+          'checker state is still FAILED');
+    };
+
+    return base.SpyPromise.run(function() {
+      fakeXhr.respond(400);
+    }).then(function() {
+      sinon.assert.calledWith(
+          onStateChange, remoting.SignalStrategy.State.FAILED);
+      assert.equal(
+          checker.getError().getTag(),
+          remoting.Error.Tag.NOT_AUTHORIZED,
+          'checker error is NOT_AUTHORIZED');
+      checkState(remoting.SignalStrategy.State.CONNECTING);
+      checkState(remoting.SignalStrategy.State.HANDSHAKE);
+      checkState(remoting.SignalStrategy.State.FAILED);
     });
-  }
-);
+  });
 
 QUnit.test('blocked after connected',
   function(assert) {
-    [
-      remoting.SignalStrategy.State.CONNECTING,
-      remoting.SignalStrategy.State.HANDSHAKE,
-    ].forEach(function(state) {
+    function checkState(state) {
       signalStrategy.setStateForTesting(state);
       sinon.assert.calledWith(onStateChange, state);
       assert.equal(checker.getState(), state);
-    });
+    };
+
+    checkState(remoting.SignalStrategy.State.CONNECTING);
+    checkState(remoting.SignalStrategy.State.HANDSHAKE);
     onStateChange.reset();
 
-    // Verify that DnsBlackholeChecker stays in HANDSHAKE state even if the
-    // signal strategy has connected.
-    signalStrategy.setStateForTesting(remoting.SignalStrategy.State.CONNECTED);
-    sinon.assert.notCalled(onStateChange);
+    // Verify that DnsBlackholeChecker stays in HANDSHAKE state even
+    // if the signal strategy has connected.
+    return base.SpyPromise.run(function() {
+      signalStrategy.setStateForTesting(
+          remoting.SignalStrategy.State.CONNECTED);
+    }).then(function() {
+      sinon.assert.notCalled(onStateChange);
     assert.equal(checker.getState(), remoting.SignalStrategy.State.HANDSHAKE);
 
-    // Verify that DnsBlackholeChecker goes to FAILED state after it gets the
-    // blocked HTTP response.
-    fakeXhrs[0].respond(400);
-    sinon.assert.calledWith(onStateChange,
-                            remoting.SignalStrategy.State.FAILED);
+      // Verify that DnsBlackholeChecker goes to FAILED state after it
+      // gets the blocked HTTP response.
+      return base.SpyPromise.run(function() {
+        fakeXhr.respond(400);
+      });
+    }).then(function() {
+      sinon.assert.calledWith(onStateChange,
+                              remoting.SignalStrategy.State.FAILED);
     assert.ok(checker.getError().hasTag(remoting.Error.Tag.NOT_AUTHORIZED));
+    });
   }
 );
 

remoting/webapp/crd/js/host_controller.js

@@ -234,14 +234,14 @@ remoting.HostController.prototype.start = function(hostPin, consent, onDone,
    * @param {string} hostName
    * @param {string} publicKey
    * @param {string} privateKey
-   * @param {XMLHttpRequest} xhr
+   * @param {!remoting.Xhr.Response} response
    */
   function onRegistered(
-      hostName, publicKey, privateKey, xhr) {
-    var success = (xhr.status == 200);
+      hostName, publicKey, privateKey, response) {
+    var success = (response.status == 200);
 
     if (success) {
-      var result = base.jsonParseSafe(xhr.responseText);
+      var result = base.jsonParseSafe(response.getText());
       if ('data' in result && 'authorizationCode' in result['data']) {
         that.hostDaemonFacade_.getCredentialsFromAuthCode(
             result['data']['authorizationCode'],
@@ -260,8 +260,8 @@ remoting.HostController.prototype.start = function(hostPin, consent, onDone,
             });
       }
     } else {
-      console.log('Failed to register the host. Status: ' + xhr.status +
-                  ' response: ' + xhr.responseText);
+      console.log('Failed to register the host. Status: ' + response.status +
+                  ' response: ' + response.getText());
       onError(new remoting.Error(remoting.Error.Tag.REGISTRATION_FAILED));
     }
   }
@@ -281,16 +281,15 @@ remoting.HostController.prototype.start = function(hostPin, consent, onDone,
        publicKey: publicKey
     } };
 
-    remoting.xhr.start({
+    new remoting.Xhr({
       method: 'POST',
       url: remoting.settings.DIRECTORY_API_BASE_URL + '/@me/hosts',
       urlParams: {
         hostClientId: hostClientId
       },
-      onDone: onRegistered.bind(null, hostName, publicKey, privateKey),
       jsonContent: newHostDetails,
       oauthToken: oauthToken
-    });
+    }).start().then(onRegistered.bind(null, hostName, publicKey, privateKey));
   }
 
   /**

remoting/webapp/crd/js/host_list_api_impl.js

@@ -28,17 +28,16 @@ remoting.HostListApiImpl = function() {
  * @param {function(!remoting.Error):void} onError
  */
 remoting.HostListApiImpl.prototype.get = function(onDone, onError) {
-  /** @type {function(XMLHttpRequest):void} */
+  /** @type {function(!remoting.Xhr.Response):void} */
   var parseHostListResponse =
       this.parseHostListResponse_.bind(this, onDone, onError);
   /** @param {string} token */
   var onToken = function(token) {
-    remoting.xhr.start({
+    new remoting.Xhr({
       method: 'GET',
       url: remoting.settings.DIRECTORY_API_BASE_URL + '/@me/hosts',
-      onDone: parseHostListResponse,
       oauthToken: token
-    });
+    }).start().then(parseHostListResponse);
   };
   remoting.identity.getToken().then(onToken, remoting.Error.handler(onError));
 };
@@ -63,13 +62,12 @@ remoting.HostListApiImpl.prototype.put =
         'publicKey': hostPublicKey
       }
     };
-    remoting.xhr.start({
+    new remoting.Xhr({
       method: 'PUT',
       url: remoting.settings.DIRECTORY_API_BASE_URL + '/@me/hosts/' + hostId,
-      onDone: remoting.xhr.defaultResponse(onDone, onError),
       jsonContent: newHostDetails,
       oauthToken: token
-    });
+    }).start().then(remoting.Xhr.defaultResponse(onDone, onError));
   };
   remoting.identity.getToken().then(onToken, remoting.Error.handler(onError));
 };
@@ -84,13 +82,12 @@ remoting.HostListApiImpl.prototype.put =
 remoting.HostListApiImpl.prototype.remove = function(hostId, onDone, onError) {
   /** @param {string} token */
   var onToken = function(token) {
-    remoting.xhr.start({
+    new remoting.Xhr({
       method: 'DELETE',
       url: remoting.settings.DIRECTORY_API_BASE_URL + '/@me/hosts/' + hostId,
-      onDone: remoting.xhr.defaultResponse(onDone, onError,
-                                           [remoting.Error.Tag.NOT_FOUND]),
       oauthToken: token
-    });
+    }).start().then(remoting.Xhr.defaultResponse(
+        onDone, onError, [remoting.Error.Tag.NOT_FOUND]));
   };
   remoting.identity.getToken().then(onToken, remoting.Error.handler(onError));
 };
@@ -102,19 +99,19 @@ remoting.HostListApiImpl.prototype.remove = function(hostId, onDone, onError) {
  *
  * @param {function(Array<remoting.Host>):void} onDone
  * @param {function(!remoting.Error):void} onError
- * @param {XMLHttpRequest} xhr
+ * @param {!remoting.Xhr.Response} response
  * @private
  */
 remoting.HostListApiImpl.prototype.parseHostListResponse_ =
-    function(onDone, onError, xhr) {
-  if (xhr.status == 200) {
-    var response = /** @type {{data: {items: Array}}} */
-        (base.jsonParseSafe(xhr.responseText));
-    if (!response || !response.data) {
+    function(onDone, onError, response) {
+  if (response.status == 200) {
+    var obj = /** @type {{data: {items: Array}}} */
+        (base.jsonParseSafe(response.getText()));
+    if (!obj || !obj.data) {
       console.error('Invalid "hosts" response from server.');
       onError(remoting.Error.unexpected());
     } else {
-      var items = response.data.items || [];
+      var items = obj.data.items || [];
       var hosts = items.map(
         function(/** Object */ item) {
           var host = new remoting.Host();
@@ -134,7 +131,7 @@ remoting.HostListApiImpl.prototype.parseHostListResponse_ =
       onDone(hosts);
     }
   } else {
-    onError(remoting.Error.fromHttpStatus(xhr.status));
+    onError(remoting.Error.fromHttpStatus(response.status));
   }
 };
 
@@ -142,4 +139,3 @@ remoting.HostListApiImpl.prototype.parseHostListResponse_ =
 remoting.hostListApi = new remoting.HostListApiImpl();
 
 })();
-

remoting/webapp/crd/js/it2me_connect_flow.js

@@ -54,8 +54,8 @@ remoting.It2MeConnectFlow.prototype.connect_ = function(accessCode) {
     return remoting.identity.getToken();
   }).then(function(/** string */ token) {
     return that.getHostInfo_(token);
-  }).then(function(/** XMLHttpRequest */ xhr) {
-    return that.onHostInfo_(xhr);
+  }).then(function(/** !remoting.Xhr.Response */ response) {
+    return that.onHostInfo_(response);
   }).then(function(/** remoting.Host */ host) {
     that.sessionConnector_.connect(
         remoting.DesktopConnectedView.Mode.IT2ME,
@@ -88,33 +88,31 @@ remoting.It2MeConnectFlow.prototype.verifyAccessCode_ = function(accessCode) {
  * Continues an IT2Me connection once an access token has been obtained.
  *
  * @param {string} token An OAuth2 access token.
- * @return {Promise<XMLHttpRequest>}
+ * @return {Promise<!remoting.Xhr.Response>}
  * @private
  */
 remoting.It2MeConnectFlow.prototype.getHostInfo_ = function(token) {
   var that = this;
-  return new Promise(function(resolve) {
-    remoting.xhr.start({
-      method: 'GET',
-      url: remoting.settings.DIRECTORY_API_BASE_URL + '/support-hosts/' +
-           encodeURIComponent(that.hostId_),
-      onDone: resolve,
-      oauthToken: token
-    });
-  });
+  return new remoting.Xhr({
+    method: 'GET',
+    url: remoting.settings.DIRECTORY_API_BASE_URL + '/support-hosts/' +
+        encodeURIComponent(that.hostId_),
+    oauthToken: token
+  }).start();
 };
 
 /**
  * Continues an IT2Me connection once the host JID has been looked up.
  *
- * @param {XMLHttpRequest} xhr The server response to the support-hosts query.
+ * @param {!remoting.Xhr.Response} xhrResponse The server response to the
+ *     support-hosts query.
  * @return {!Promise<!remoting.Host>} Rejects on error.
  * @private
  */
-remoting.It2MeConnectFlow.prototype.onHostInfo_ = function(xhr) {
-  if (xhr.status == 200) {
+remoting.It2MeConnectFlow.prototype.onHostInfo_ = function(xhrResponse) {
+  if (xhrResponse.status == 200) {
     var response = /** @type {{data: {jabberId: string, publicKey: string}}} */
-        (base.jsonParseSafe(xhr.responseText));
+        (base.jsonParseSafe(xhrResponse.getText()));
     if (response && response.data &&
         response.data.jabberId && response.data.publicKey) {
       var host = new remoting.Host();
@@ -128,11 +126,12 @@ remoting.It2MeConnectFlow.prototype.onHostInfo_ = function(xhr) {
       return Promise.reject(remoting.Error.unexpected());
     }
   } else {
-    return Promise.reject(translateSupportHostsError(xhr.status));
+    return Promise.reject(translateSupportHostsError(xhrResponse.status));
   }
 };
 
 /**
+ * TODO(jrw): Replace with remoting.Error.fromHttpStatus.
  * @param {number} error An HTTP error code returned by the support-hosts
  *     endpoint.
  * @return {remoting.Error} The equivalent remoting.Error code.

remoting/webapp/crd/js/oauth2.js

@@ -250,7 +250,7 @@ remoting.OAuth2.prototype.onTokens_ =
 remoting.OAuth2.prototype.getAuthorizationCode = function(onDone) {
   var xsrf_token = base.generateXsrfToken();
   var GET_CODE_URL = this.getOAuth2AuthEndpoint_() + '?' +
-    remoting.xhr.urlencodeParamHash({
+    remoting.Xhr.urlencodeParamHash({
           'client_id': this.getClientId_(),
           'redirect_uri': this.getRedirectUri_(),
           'scope': this.SCOPE_,

remoting/webapp/crd/js/oauth2_api_impl.js

@@ -75,37 +75,36 @@ remoting.OAuth2ApiImpl.prototype.interpretXhrStatus_ =
  */
 remoting.OAuth2ApiImpl.prototype.refreshAccessToken = function(
     onDone, onError, clientId, clientSecret, refreshToken) {
-  /** @param {XMLHttpRequest} xhr */
-  var onResponse = function(xhr) {
-    if (xhr.status == 200) {
+  /** @param {!remoting.Xhr.Response} response */
+  var onResponse = function(response) {
+    if (response.status == 200) {
       try {
         // Don't use base.jsonParseSafe here unless you also include base.js,
         // otherwise this won't work from the OAuth trampoline.
         // TODO(jamiewalch): Fix this once we're no longer using the trampoline.
-        var tokens = JSON.parse(xhr.responseText);
+        var tokens = JSON.parse(response.getText());
         onDone(tokens['access_token'], tokens['expires_in']);
       } catch (/** @type {Error} */ err) {
         console.error('Invalid "token" response from server:', err);
         onError(remoting.Error.unexpected());
       }
     } else {
-      console.error('Failed to refresh token. Status: ' + xhr.status +
-                    ' response: ' + xhr.responseText);
-      onError(fromHttpStatus(xhr.status));
+      console.error('Failed to refresh token. Status: ' + response.status +
+                    ' response: ' + response.getText());
+      onError(remoting.Error.fromHttpStatus(response.status));
     }
   };
 
-  remoting.xhr.start({
+  new remoting.Xhr({
     method: 'POST',
     url: this.getOAuth2TokenEndpoint_(),
-    onDone: onResponse,
     formContent: {
       'client_id': clientId,
       'client_secret': clientSecret,
       'refresh_token': refreshToken,
       'grant_type': 'refresh_token'
     }
-  });
+  }).start().then(onResponse);
 };
 
 /**
@@ -124,14 +123,14 @@ remoting.OAuth2ApiImpl.prototype.refreshAccessToken = function(
  */
 remoting.OAuth2ApiImpl.prototype.exchangeCodeForTokens = function(
     onDone, onError, clientId, clientSecret, code, redirectUri) {
-  /** @param {XMLHttpRequest} xhr */
-  var onResponse = function(xhr) {
-    if (xhr.status == 200) {
+  /** @param {!remoting.Xhr.Response} response */
+  var onResponse = function(response) {
+    if (response.status == 200) {
       try {
         // Don't use base.jsonParseSafe here unless you also include base.js,
         // otherwise this won't work from the OAuth trampoline.
         // TODO(jamiewalch): Fix this once we're no longer using the trampoline.
-        var tokens = JSON.parse(xhr.responseText);
+        var tokens = JSON.parse(response.getText());
         onDone(tokens['refresh_token'],
                tokens['access_token'], tokens['expires_in']);
       } catch (/** @type {Error} */ err) {
@@ -139,16 +138,15 @@ remoting.OAuth2ApiImpl.prototype.exchangeCodeForTokens = function(
         onError(remoting.Error.unexpected());
       }
     } else {
-      console.error('Failed to exchange code for token. Status: ' + xhr.status +
-                    ' response: ' + xhr.responseText);
-      onError(fromHttpStatus(xhr.status));
+      console.error('Failed to exchange code for token. Status: ' +
+                    response.status + ' response: ' + response.getText());
+      onError(remoting.Error.fromHttpStatus(response.status));
     }
   };
 
-  remoting.xhr.start({
+  new remoting.Xhr({
     method: 'POST',
     url: this.getOAuth2TokenEndpoint_(),
-    onDone: onResponse,
     formContent: {
       'client_id': clientId,
       'client_secret': clientSecret,
@@ -156,7 +154,7 @@ remoting.OAuth2ApiImpl.prototype.exchangeCodeForTokens = function(
       'code': code,
       'grant_type': 'authorization_code'
     }
-  });
+  }).start().then(onResponse);
 };
 
 /**
@@ -170,28 +168,27 @@ remoting.OAuth2ApiImpl.prototype.exchangeCodeForTokens = function(
  * @return {void} Nothing.
  */
 remoting.OAuth2ApiImpl.prototype.getEmail = function(onDone, onError, token) {
-  /** @param {XMLHttpRequest} xhr */
-  var onResponse = function(xhr) {
-    if (xhr.status == 200) {
+  /** @param {!remoting.Xhr.Response} response */
+  var onResponse = function(response) {
+    if (response.status == 200) {
       try {
-        var result = JSON.parse(xhr.responseText);
+        var result = JSON.parse(response.getText());
         onDone(result['email']);
       } catch (/** @type {Error} */ err) {
         console.error('Invalid "userinfo" response from server:', err);
         onError(remoting.Error.unexpected());
       }
     } else {
-      console.error('Failed to get email. Status: ' + xhr.status +
-                    ' response: ' + xhr.responseText);
-      onError(fromHttpStatus(xhr.status));
+      console.error('Failed to get email. Status: ' + response.status +
+                    ' response: ' + response.getText());
+      onError(remoting.Error.fromHttpStatus(response.status));
     }
   };
-  remoting.xhr.start({
+  new remoting.Xhr({
     method: 'GET',
     url: this.getOAuth2ApiUserInfoEndpoint_(),
-    onDone: onResponse,
     oauthToken: token
-  });
+  }).start().then(onResponse);
 };
 
 /**
@@ -206,28 +203,27 @@ remoting.OAuth2ApiImpl.prototype.getEmail = function(onDone, onError, token) {
  */
 remoting.OAuth2ApiImpl.prototype.getUserInfo =
     function(onDone, onError, token) {
-  /** @param {XMLHttpRequest} xhr */
-  var onResponse = function(xhr) {
-    if (xhr.status == 200) {
+  /** @param {!remoting.Xhr.Response} response */
+  var onResponse = function(response) {
+    if (response.status == 200) {
       try {
-        var result = JSON.parse(xhr.responseText);
+        var result = JSON.parse(response.getText());
         onDone(result['email'], result['name']);
       } catch (/** @type {Error} */ err) {
         console.error('Invalid "userinfo" response from server:', err);
         onError(remoting.Error.unexpected());
       }
     } else {
-      console.error('Failed to get user info. Status: ' + xhr.status +
-                    ' response: ' + xhr.responseText);
-      onError(fromHttpStatus(xhr.status));
+      console.error('Failed to get user info. Status: ' + response.status +
+                    ' response: ' + response.getText());
+      onError(remoting.Error.fromHttpStatus(response.status));
     }
   };
-  remoting.xhr.start({
+  new remoting.Xhr({
     method: 'GET',
     url: this.getOAuth2ApiUserInfoEndpoint_(),
-    onDone: onResponse,
     oauthToken: token
-  });
+  }).start().then(onResponse);
 };
 
 /** @returns {!remoting.Error} */

remoting/webapp/crd/js/session_connector_impl.js

@@ -75,6 +75,9 @@ remoting.SessionConnectorImpl = function(clientContainer, onConnected, onError,
 remoting.SessionConnectorImpl.prototype.resetConnection_ = function() {
   this.closeSession();
 
+  // It's OK to initialize these member variables here because the
+  // constructor calls this method.
+
   /** @private {remoting.Host} */
   this.host_ = null;
 
@@ -87,8 +90,6 @@ remoting.SessionConnectorImpl.prototype.resetConnection_ = function() {
   /** @private {remoting.ClientSession} */
   this.clientSession_ = null;
 
-  /** @private {XMLHttpRequest} */
-  this.pendingXhr_ = null;
 
   /** @private {remoting.CredentialsProvider} */
   this.credentialsProvider_ = null;

remoting/webapp/crd/js/third_party_token_fetcher.js

@@ -132,7 +132,7 @@ remoting.ThirdPartyTokenFetcher.prototype.parseRedirectUrl_ =
  * @private
  */
 remoting.ThirdPartyTokenFetcher.prototype.getFullTokenUrl_ = function() {
-  return this.tokenUrl_ + '?' + remoting.xhr.urlencodeParamHash({
+  return this.tokenUrl_ + '?' + remoting.Xhr.urlencodeParamHash({
     'redirect_uri': this.redirectUri_,
     'scope': this.tokenScope_,
     'client_id': this.hostPublicKey_,

remoting/webapp/js_proto/qunit_proto.js

@@ -100,4 +100,4 @@ QUnit.module = function(desc, opt_args) {};
  * @param {string} desc
  * @param {function(QUnit.Assert)} f
  */
-QUnit.test = function(desc, f) {};
+QUnit.test = function(desc, f) {};
\ No newline at end of file

remoting/webapp/js_proto/sinon_proto.js

@@ -126,3 +126,36 @@ sinon.TestStub.prototype.onFirstCall = function() {};
 
 /** @returns {Object}  */
 sinon.createStubInstance = function (/** * */ constructor) {};
+
+/** @return {sinon.FakeXhr} */
+sinon.useFakeXMLHttpRequest = function() {};
+
+/** @interface */
+sinon.FakeXhr = function() {};
+
+/** @type {string} */
+sinon.FakeXhr.prototype.method;
+
+/** @type {string} */
+sinon.FakeXhr.prototype.url;
+
+/** @type {boolean} */
+sinon.FakeXhr.prototype.withCredentials;
+
+/** @type {?string} */
+sinon.FakeXhr.prototype.requestBody;
+
+/** @type {!Object<string,string>} */
+sinon.FakeXhr.prototype.requestHeaders;
+
+/**
+ * @param {number} status
+ * @param {!Object<string,string>} headers
+ * @param {?string} content
+ */
+sinon.FakeXhr.prototype.respond;
+
+/**
+ * @type {?function(!sinon.FakeXhr)}
+ */
+sinon.FakeXhr.prototype.onCreate;
\ No newline at end of file