Allow a closure to be torn off from itself via .call.

sdk/lib/_internal/compiler/implementation/js_emitter/class_emitter.dart

Index: sdk/lib/_internal/compiler/implementation/js_emitter/class_emitter.dart
diff --git a/sdk/lib/_internal/compiler/implementation/js_emitter/class_emitter.dart b/sdk/lib/_internal/compiler/implementation/js_emitter/class_emitter.dart
index 6f19edbabfb30fca42b91aafa3009a93424c6f80..af06202c35071606fce8335828ee17863471d572 100644
--- a/sdk/lib/_internal/compiler/implementation/js_emitter/class_emitter.dart
+++ b/sdk/lib/_internal/compiler/implementation/js_emitter/class_emitter.dart
@@ -47,6 +47,14 @@ class ClassEmitter extends CodeEmitterHelper {
       additionalProperties.forEach(builder.addProperty);
     }
 
+    if (classElement == compiler.closureClass) {
+      // We add a special getter here to allow for tearing off a closure form

[karlklose, 2014/04/28 07:04:23]

'form' -> 'from'.

+      // itself.
+      String name = namer.safeName(Compiler.CALL_OPERATOR_NAME);
+      jsAst.Fun function = js('function() { return this; }');
+      builder.addProperty(namer.getterNameFromAccessorName(name), function);
+    }
+
     emitTypeVariableReaders(classElement, builder);
 
     emitClassBuilderWithReflectionData(