dart2js: Remove obsolete comment and code.

pkg/compiler/lib/src/js_emitter/native_emitter.dart

Index: pkg/compiler/lib/src/js_emitter/native_emitter.dart
diff --git a/pkg/compiler/lib/src/js_emitter/native_emitter.dart b/pkg/compiler/lib/src/js_emitter/native_emitter.dart
index 1817b09ef8ef6d93629904cdd6d0200d88ec3bf2..abe77950b226b8acb263c7678b4ab68e8c973737 100644
--- a/pkg/compiler/lib/src/js_emitter/native_emitter.dart
+++ b/pkg/compiler/lib/src/js_emitter/native_emitter.dart
@@ -282,11 +282,7 @@ class NativeEmitter {
 
     ClassElement superclass = classElement.superclass;
     assert(superclass != null);
-    // Fix superclass.  TODO(sra): make native classes inherit from Interceptor.
     assert(superclass != compiler.objectClass);
-    if (superclass == compiler.objectClass) {
-      superclass = backend.jsInterceptorClass;
-    }
 
     String superName = backend.namer.getNameOfClass(superclass);