Reverting "Adding CORS support to HttpRequest"

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 7ae7698d7cf50d2180b7cde41b3edf7c8e7103e6..5e0f8b814b04da090af018d4334e7cb6ca019f83 100644
--- a/tools/dom/templates/html/impl/impl_XMLHttpRequest.darttemplate
+++ b/tools/dom/templates/html/impl/impl_XMLHttpRequest.darttemplate
@@ -129,23 +129,7 @@ $(ANNOTATIONS)class $CLASSNAME$EXTENDS$IMPLEMENTS$NATIVESPEC {
   static bool get supportsProgressEvent {
 $if DART2JS
     var xhr = new HttpRequest();
-    return JS('bool', '("onprogress" in #)', xhr);
-$else
-    return true;
-$endif
-  }
-
-  /**
-   * Checks to see if the current platform supports making cross origin
-   * requests.
-   *
-   * Note that even if cross origin requests are supported, they still may fail
-   * if the destination server does not support CORS requests.
-   */
-  static bool get supportsCrossOrigin {
-$if DART2JS
-    var xhr = new HttpRequest();
-    return JS('bool', '("withCredentials" in #)', xhr);
+    return JS('bool', '"onprogress" in #', xhr);
 $else
     return true;
 $endif
@@ -157,7 +141,7 @@ $endif
   static bool get supportsLoadEndEvent {
 $if DART2JS
     var xhr = new HttpRequest();
-    return JS('bool', '("onloadend" in #)', xhr);
+    return JS('bool', '"onloadend" in #', xhr);
 $else
     return true;
 $endif