Add support for closure calls through getters.

sdk/lib/_internal/lib/js_helper.dart

Index: sdk/lib/_internal/lib/js_helper.dart
diff --git a/sdk/lib/_internal/lib/js_helper.dart b/sdk/lib/_internal/lib/js_helper.dart
index 76d615f6fbb893eff708514ede31bea01d1e04a3..97e4a5b99bb408ecf2077c581a2d148ec455627c 100644
--- a/sdk/lib/_internal/lib/js_helper.dart
+++ b/sdk/lib/_internal/lib/js_helper.dart
@@ -150,8 +150,7 @@ class JSInvocationMirror implements Invocation {
 
   List get positionalArguments {
     if (isGetter) return const [];
-    var argumentCount =
-        _arguments.length - _namedArgumentNames.length;
+    var argumentCount = _arguments.length - _namedArgumentNames.length;
     if (argumentCount == 0) return const [];
     var list = [];
     for (var index = 0 ; index < argumentCount ; index++) {
@@ -274,6 +273,7 @@ class CachedInvocation {
                    this.cachedInterceptor);
 
   bool get isNoSuchMethod => false;
+  bool get isGetterStub => JS("bool", "!!#.\$getterStub", jsFunction);
 
   /// Applies [jsFunction] to [victim] with [arguments].
   /// Users of this class must take care to check the arguments first.
@@ -299,6 +299,8 @@ class CachedCatchAllInvocation extends CachedInvocation {
       : info = new ReflectionInfo(jsFunction),
         super(name, jsFunction, isIntercepted, cachedInterceptor);
 
+  bool get isGetterStub => false;
+
   invokeOn(Object victim, List arguments) {
     var receiver = victim;
     int providedArgumentCount;
@@ -350,6 +352,7 @@ class CachedNoSuchMethodInvocation {
   CachedNoSuchMethodInvocation(this.interceptor);
 
   bool get isNoSuchMethod => true;
+  bool get isGetterStub => false;
 
   invokeOn(Object victim, Invocation invocation) {
     var receiver = (interceptor == null) ? victim : interceptor;