isJavaScriptPromise needs to handle Promise not being defined (IE)

sdk/lib/html/html_common/conversions_dart2js.dart

Index: sdk/lib/html/html_common/conversions_dart2js.dart
diff --git a/sdk/lib/html/html_common/conversions_dart2js.dart b/sdk/lib/html/html_common/conversions_dart2js.dart
index d0b7d77e217a968c4d22fccfa6867c41efa33dc8..ac5b7554de34e5956e2ec596a4299dd9d1850916 100644
--- a/sdk/lib/html/html_common/conversions_dart2js.dart
+++ b/sdk/lib/html/html_common/conversions_dart2js.dart
@@ -81,7 +81,8 @@ bool isJavaScriptSimpleObject(value) {
 }
 bool isImmutableJavaScriptArray(value) =>
     JS('bool', r'!!(#.immutable$list)', value);
-bool isJavaScriptPromise(value) => JS('bool', r'# instanceof Promise', value);
+bool isJavaScriptPromise(value) =>
+    JS('bool', r'typeof Promise != "undefined" && # instanceof Promise', value);
 
 Future convertNativePromiseToDartFuture(promise) {
   var completer = new Completer();