fix(xhr2): handle FormData response type

external/xhr2.js

-// Generated by CoffeeScript 1.12.2
+// Generated by CoffeeScript 1.12.7
 (function() {
   var InvalidStateError, NetworkError, ProgressEvent, SecurityError, SyntaxError, XMLHttpRequest, XMLHttpRequestEventTarget, XMLHttpRequestUpload, http, https, os, url,
     extend = function(child, parent) { for (var key in parent) { if (hasProp.call(parent, key)) child[key] = parent[key]; } function ctor() { this.constructor = child; } ctor.prototype = parent.prototype; child.prototype = new ctor(); child.__super__ = parent.prototype; return child; },
@@ -323,7 +323,7 @@
       'access-control-request-method': true,
       connection: true,
       'content-length': true,
-      // cookie: true,
+      cookie: true,
       cookie2: true,
       date: true,
       dnt: true,
@@ -341,7 +341,7 @@
     };
 
     XMLHttpRequest.prototype._privateHeaders = {
-      // 'set-cookie': true,
+      'set-cookie': true,
       'set-cookie2': true
     };
 
@@ -363,6 +363,7 @@
     };
 
     XMLHttpRequest.prototype._sendHttp = function(data) {
+      var that;
       if (this._sync) {
         throw new Error("Synchronous XHR processing not implemented");
       }
@@ -372,9 +373,11 @@
       } else {
         data || (data = '');
       }
-      this.upload._setData(data);
-      this._finalizeHeaders();
-      this._sendHxxpRequest();
+      that = this;
+      this.upload._setData(data, function() {
+        that._finalizeHeaders();
+        return that._sendHxxpRequest();
+      });
       return void 0;
     };
 
@@ -709,11 +712,13 @@
 
   XMLHttpRequest.XMLHttpRequest = XMLHttpRequest;
 
+  XMLHttpRequest.FormData = FormData;
+
   SecurityError = (function(superClass) {
     extend(SecurityError, superClass);
 
     function SecurityError() {
-      SecurityError.__super__.constructor.apply(this, arguments);
+      SecurityError.__super__.constructor.call(this);
     }
 
     return SecurityError;
@@ -726,7 +731,7 @@
     extend(InvalidStateError, superClass);
 
     function InvalidStateError() {
-      InvalidStateError.__super__.constructor.apply(this, arguments);
+      InvalidStateError.__super__.constructor.call(this);
     }
 
     return InvalidStateError;
@@ -750,7 +755,7 @@
     extend(NetworkError, superClass);
 
     function NetworkError() {
-      NetworkError.__super__.constructor.apply(this, arguments);
+      NetworkError.__super__.constructor.call(this);
     }
 
     return NetworkError;
@@ -763,7 +768,7 @@
     extend(SyntaxError, superClass);
 
     function SyntaxError() {
-      SyntaxError.__super__.constructor.apply(this, arguments);
+      SyntaxError.__super__.constructor.call(this);
     }
 
     return SyntaxError;
@@ -813,10 +818,10 @@
       return void 0;
     };
 
-    XMLHttpRequestUpload.prototype._setData = function(data) {
-      var body, i, j, k, offset, ref, ref1, view;
+    XMLHttpRequestUpload.prototype._setData = function(data, cb) {
+      var body, i, j, k, offset, ref, ref1, that, view;
       if (typeof data === 'undefined' || data === null) {
-        return;
+        return cb();
       }
       if (typeof data === 'string') {
         if (data.length !== 0) {
@@ -840,10 +845,23 @@
           body[i] = view[i + offset];
         }
         this._body = body;
+      } else if (data instanceof FormData) {
+        body = '';
+        this._contentType = data.getHeaders()['content-type'];
+        data.on('data', function(data) {
+          return body += data.toString();
+        });
+        that = this;
+        data.on('end', function() {
+          that._body = body;
+          return cb();
+        });
+        data.resume();
+        return;
       } else {
         throw new Error("Unsupported send() data " + data);
       }
-      return void 0;
+      return cb();
     };
 
     XMLHttpRequestUpload.prototype._finalizeHeaders = function(headers, loweredHeaders) {