Add zone task support to http-requests.

tools/dom/templates/html/impl/impl_XMLHttpRequest.darttemplate

Index: tools/dom/templates/html/impl/impl_XMLHttpRequest.darttemplate
diff --git a/tools/dom/templates/html/impl/impl_XMLHttpRequest.darttemplate b/tools/dom/templates/html/impl/impl_XMLHttpRequest.darttemplate
index 9ad00f61c2c2053f97c229ee85a0ffa0b1dd0b83..e586de83cda8264ba47f31efc28e7ac9aea7dc55 100644
--- a/tools/dom/templates/html/impl/impl_XMLHttpRequest.darttemplate
+++ b/tools/dom/templates/html/impl/impl_XMLHttpRequest.darttemplate
@@ -4,6 +4,67 @@
 
 part of $LIBRARYNAME;
 
+/**
+ * A task specification for http requests.
+ *
+ * This specification is not available when an http request is sent through
+ * direct use of [HttpRequest.send]. See [HttpRequestSendTaskSpecification].
+ *
+ * A task created by this specification is a `Future<HttpRequest>`.
+ */
+class HttpRequestTaskSpecification extends TaskSpecification {
+  final String url;

[Lasse Reichstein Nielsen, 2016/06/08 09:40:28]

Document fields (e.g., by referencing the XmlHttpRequest object or its method
parameters).

[floitsch, 2016/06/10 15:46:57]

Done.

+  final String method;
+  final bool withCredentials;
+  final String responseType;
+  final String mimeType;
+  final Map<String, String> requestHeaders;
+  final dynamic sendData;
+  /**
+   * The function that is invoked on progress updates. This function is *not*
+   * executed as part of the http-request task, but as an event callback.

[Lasse Reichstein Nielsen, 2016/06/08 09:40:28]

I don't understand what it means to be "part of the http-request task" and how
an event callback is different. Try rewording.

[floitsch, 2016/06/10 15:46:57]

Done.

+   *
+   * Creating an http-request automatically registers the on-progress listener.
+   */
+  final ZoneUnaryCallback<dynamic, ProgressEvent> onProgress;
+
+  HttpRequestTaskSpecification(this.url,
+      {String this.method, bool this.withCredentials, String this.responseType,
+      String this.mimeType, Map<String, String> this.requestHeaders,
+      this.sendData,
+      void this.onProgress(ProgressEvent e)});
+
+  String get name => "dart.html.http-request";
+  bool get isOneShot => true;
+}
+
+/**
+ * A task specification for http requests that are initiated through a direct
+ * invocation of [HttpRequest.send].
+ *
+ * This specification serves as signal to zones that an http request has been

[Lasse Reichstein Nielsen, 2016/06/08 09:40:28]

http -> HTTP
acronym, dittos below.

[floitsch, 2016/06/10 15:46:57]

Done.

+ * initiated. The created task is the [request] object itself, and
+ * no callback is ever executed in this task. When the http request gets
+ * data event-listeners that have the request object as event target are

[Lasse Reichstein Nielsen, 2016/06/08 09:40:28]

commas in this sentence? I have a hard time parsing it.
"gets" -> "receives"?

What is the "request object"?

[floitsch, 2016/06/10 15:46:57]

Reworded.
Done.

+ * executed.
+ *
+ * Http requests that are initiated through `request` methods don't use
+ * this class but use [HttpRequestTaskSpecification].
+ */
+class HttpRequestSendTaskSpecification extends TaskSpecification {
+  final HttpRequest request;
+  final dynamic sendData;
+
+  HttpRequestSendTaskSpecification(this.request, this.sendData);
+
+  String get name => "dart.html.http-request-send";
+
+  /**
+   * No callback is ever executed in an http-request send task.
+   */
+  bool get isOneShot => false;
+}
+
  /**
   * A client-side XHR request for getting data from a URL,
   * formally known as XMLHttpRequest.
@@ -190,7 +251,34 @@ $(ANNOTATIONS)$(NATIVESPEC)$(CLASS_MODIFIERS)class $CLASSNAME$EXTENDS$IMPLEMENTS
       {String method, bool withCredentials, String responseType,
       String mimeType, Map<String, String> requestHeaders, sendData,
       void onProgress(ProgressEvent e)}) {
+    var spec = new HttpRequestTaskSpecification(
+        url, method: method,
+        withCredentials: withCredentials,
+        responseType: responseType,
+        mimeType: mimeType,
+        requestHeaders: requestHeaders,
+        sendData: sendData,
+        onProgress: onProgress);
+
+    if (identical(Zone.current, Zone.ROOT)) {
+      return _createHttpRequestTask(spec, null);
+    }
+    return Zone.current.createTask(_createHttpRequestTask, spec);
+  }
+
+  static Future<HttpRequest> _createHttpRequestTask(
+      HttpRequestTaskSpecification spec, Zone zone) {
+    String url = spec.url;
+    String method = spec.method;
+    bool withCredentials = spec.withCredentials;
+    String responseType = spec.responseType;
+    String mimeType = spec.mimeType;
+    Map<String, String> requestHeaders = spec.requestHeaders;
+    var sendData = spec.sendData;
+    var onProgress = spec.onProgress;
+
     var completer = new Completer<HttpRequest>();
+    var task = completer.future;
 
     var xhr = new HttpRequest();
     if (method == null) {
@@ -230,23 +318,42 @@ $(ANNOTATIONS)$(NATIVESPEC)$(CLASS_MODIFIERS)class $CLASSNAME$EXTENDS$IMPLEMENTS
       // redirect case will be handled by the browser before it gets to us,
       // so if we see it we should pass it through to the user.
       var unknownRedirect = xhr.status > 307 && xhr.status < 400;
-      
-      if (accepted || fileUri || notModified || unknownRedirect) {
+
+      var isSuccessful = accepted || fileUri || notModified || unknownRedirect;
+
+      if (zone == null && isSuccessful) {
         completer.complete(xhr);
-      } else {
+      } else if (zone == null) {
         completer.completeError(e);
+      } else if (isSuccessful) {
+        zone.runTask((task, value) {
+          completer.complete(value);
+        }, task, xhr);
+      } else {
+        zone.runTask((task, error) {
+          completer.completeError(error);
+        }, task, e);
       }
     });
 
-    xhr.onError.listen(completer.completeError);
+    if (zone == null) {
+      xhr.onError.listen(completer.completeError);
+    } else {
+      xhr.onError.listen((error) {
+        zone.runTask((task, error) {
+          completer.completeError(error);
+        }, task, error);
+      });
+    }
 
     if (sendData != null) {
-      xhr.send(sendData);
+      // TODO(floitsch): should we go through 'send()' and have nested tasks?
+      xhr._send(sendData);
     } else {
-      xhr.send();
+      xhr._send();
     }
 
-    return completer.future;
+    return task;
   }
 
   /**
@@ -316,6 +423,9 @@ $endif
         return xhr.responseText;
       });
     }
+    // TODO(floitsch): the following code doesn't go through task zones.
+    // Since 'XDomainRequest' is an IE9 feature we should probably just remove
+    // it.
 $if DART2JS
     var completer = new Completer<String>();
     if (method == null) {
@@ -396,7 +506,7 @@ $endif
    *
    * Note: Most simple HTTP requests can be accomplished using the [getString],
    * [request], [requestCrossOrigin], or [postFormData] methods. Use of this
-   * `open` method is intended only for more complext HTTP requests where
+   * `open` method is intended only for more complex HTTP requests where
    * finer-grained control is needed.
    */
   @DomName('XMLHttpRequest.open')
@@ -413,5 +523,35 @@ $else
   void open(String method, String url, {bool async, String user, String password}) native;
 $endif
 
+  /**
+   * Sends the request with any given `data`.
+   *
+   * Note: Most simple HTTP requests can be accomplished using the [getString],
+   * [request], [requestCrossOrigin], or [postFormData] methods. Use of this
+   * `send` method is intended only for more complex HTTP requests where
+   * finer-grained control is needed.
+   *
+   * ## Other resources
+   *
+   * * [XMLHttpRequest.send](https://developer.mozilla.org/en-US/docs/DOM/XMLHttpRequest#send%28%29)
+   *   from MDN.
+   */
+  @DomName('XMLHttpRequest.send')
+  @DocsEditable()
+  void send([body_OR_data]) {
+    if (identical(Zone.current, Zone.ROOT)) {
+      _send(body_OR_data);
+    } else {
+      Zone.current.createTask(_createHttpRequestSendTask,
+          new HttpRequestSendTaskSpecification(this, body_OR_data));
+    }
+  }
+
+  static HttpRequest _createHttpRequestSendTask(
+      HttpRequestSendTaskSpecification spec, Zone zone) {
+    spec.request._send(spec.sendData);
+    return spec.request;
+  }
+
 $!MEMBERS
 }