Merge pull request #10 in AOLP_ADS_JS/prebid.js from feature/re-enabl…

…e_ajax_tracking_requests to master

* commit '0f92570fa8327bd504e9b05e9667ac225dfc16c4':
  Re-enable ajax tracking requests. Ensure that withCredentials flag is set.

src/adapters/analytics/aol.js

@@ -126,8 +126,7 @@ export default utils.extend(adapter({
     },
 
     reportEvent(url) {
-      var pixel = new Image();
-      pixel.src = url;
+      ajax(url, null, null, null, {isTrackingRequest: true});
     },
 
     getBaseSchema(eventId, adUnit) {

src/ajax.js

@@ -8,9 +8,12 @@
  * @param callback object callback
  * @param data mixed data
  * @param x null Ajax request
+ * @param options.isTrackingRequest set to true to denote the request
+ *     is for tracking purposes, as opposed to loading remote data.
  */
 
-export const ajax = function ajax(url, callback, data, x = null) {
+export const ajax = function ajax(url, callback, data, x = null,
+                                  options = {isTrackingRequest: false }) {
   try {
     if (window.XMLHttpRequest) {
       x = new window.XMLHttpRequest('MSXML2.XMLHTTP.3.0');
@@ -22,8 +25,12 @@ export const ajax = function ajax(url, callback, data, x = null) {
 
     //x = new (window.XMLHttpRequest || window.ActiveXObject)('MSXML2.XMLHTTP.3.0');
     x.open(data ? 'POST' : 'GET', url, 1);
-    x.setRequestHeader('X-Requested-With', 'XMLHttpRequest');
-    x.setRequestHeader('Content-Type', 'application/json;charset=UTF-8');
+    if (options.isTrackingRequest) {
+      x.withCredentials = true;
+    } else {
+      x.setRequestHeader('X-Requested-With', 'XMLHttpRequest');
+      x.setRequestHeader('Content-Type', 'application/json;charset=UTF-8');
+    }
 
     //x.setRequestHeader('Content-type', 'application/x-www-form-urlencoded');
     x.onreadystatechange = function () {