import FIREFOX_52_6_0esr_RELEASE from mozilla-esr52 hg repo

toolkit/modules/ServiceRequest.jsm

@@ -0,0 +1,49 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+"use strict";
+
+const { classes: Cc, interfaces: Ci, results: Cr, utils: Cu } = Components;
+
+/**
+  * This module consolidates various code and data update requests, so flags
+  * can be set, Telemetry collected, etc. in a central place.
+  */
+
+Cu.import("resource://gre/modules/Log.jsm");
+Cu.importGlobalProperties(["XMLHttpRequest"]);
+
+this.EXPORTED_SYMBOLS = [ "ServiceRequest" ];
+
+const logger = Log.repository.getLogger("ServiceRequest");
+logger.level = Log.Level.Debug;
+logger.addAppender(new Log.ConsoleAppender(new Log.BasicFormatter()));
+
+/**
+  * ServiceRequest is intended to be a drop-in replacement for current users
+  * of XMLHttpRequest.
+  *
+  * @param {Object} options - Options for underlying XHR, e.g. { mozAnon: bool }
+  */
+class ServiceRequest extends XMLHttpRequest {
+  constructor(options) {
+    super(options);
+  }
+  /**
+    * Opens an XMLHttpRequest, and sets the NSS "beConservative" flag.
+    * Requests are always async.
+    *
+    * @param {String} method - HTTP method to use, e.g. "GET".
+    * @param {String} url - URL to open.
+    * @param {Object} options - Additional options (reserved for future use).
+    */
+  open(method, url, options) {
+    super.open(method, url, true);
+
+    // Disable cutting edge features, like TLS 1.3, where middleboxes might brick us
+    if (super.channel instanceof Ci.nsIHttpChannelInternal) {
+      super.channel.QueryInterface(Ci.nsIHttpChannelInternal).beConservative = true;
+    }
+  }
+}