Support runtime check of function types.

sdk/lib/_internal/compiler/implementation/ssa/codegen.dart

Index: sdk/lib/_internal/compiler/implementation/ssa/codegen.dart
diff --git a/sdk/lib/_internal/compiler/implementation/ssa/codegen.dart b/sdk/lib/_internal/compiler/implementation/ssa/codegen.dart
index b8843daeccf1b6463040a086003dc590c87d75b3..9aac0855f6c1c8d173018cb0dfd3047623b510bc 100644
--- a/sdk/lib/_internal/compiler/implementation/ssa/codegen.dart
+++ b/sdk/lib/_internal/compiler/implementation/ssa/codegen.dart
@@ -2244,9 +2244,10 @@ abstract class SsaCodeGenerator implements HVisitor, HBlockInformationVisitor {
                      message: 'Attempt to check malformed type $type'));
     world.registerIsCheck(type, work.resolutionTree);
     Element element = type.element;
+    String operatorIs = backend.namer.operatorIsType(type);
     use(input);
     js.PropertyAccess field =
-        new js.PropertyAccess.field(pop(), backend.namer.operatorIs(element));
+        new js.PropertyAccess.field(pop(), operatorIs);
     if (backend.emitter.nativeEmitter.requiresNativeIsCheck(element)) {
       push(new js.Call(field, <js.Expression>[]));
       if (negative) push(new js.Prefix('!', pop()));
@@ -2426,7 +2427,7 @@ abstract class SsaCodeGenerator implements HVisitor, HBlockInformationVisitor {
         // 2 arguments implies that the method is either [propertyTypeCheck]
         // or [propertyTypeCast].
         assert(!type.isMalformed);
-        String additionalArgument = backend.namer.operatorIs(type.element);
+        String additionalArgument = backend.namer.operatorIsType(type);
         arguments.add(js.string(additionalArgument));
       } else if (parameterCount == 3) {
         // 3 arguments implies that the method is [malformedTypeCheck].