new classes: implement default constructors.

src/runtime/runtime-classes.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <stdlib.h>
 #include <limits>
 
 #include "src/v8.h"
 
 #include "src/isolate-inl.h"
@@ skipping 396 matching lines @@
   DCHECK(args.length() == 4);
   CONVERT_ARG_HANDLE_CHECKED(Object, receiver, 0);
   CONVERT_ARG_HANDLE_CHECKED(JSObject, home_object, 1);
   CONVERT_ARG_HANDLE_CHECKED(Object, key, 2);
   CONVERT_ARG_HANDLE_CHECKED(Object, value, 3);
 
   return StoreKeyedToSuper(isolate, home_object, receiver, key, value, SLOPPY);
 }
 
 
+RUNTIME_FUNCTION(RuntimeReference_DefaultConstructorCallSuper) {
+  UNREACHABLE();
+  return nullptr;
+}
+
+
+// TODO(dslomov): deprecated, will remove when experimenal classes is default.
 RUNTIME_FUNCTION(Runtime_DefaultConstructorSuperCall) {
+  CHECK(!FLAG_experimental_classes);
   HandleScope scope(isolate);
   DCHECK(args.length() == 0);
 
   // Compute the frame holding the arguments.
   JavaScriptFrameIterator it(isolate);
   it.AdvanceToArgumentsFrame();
   JavaScriptFrame* frame = it.frame();
 
   Handle<JSFunction> function(frame->function(), isolate);
   Handle<Object> receiver(frame->receiver(), isolate);
@@ skipping 26 matching lines @@
   }
 
   Handle<Object> result;
   ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
       isolate, result,
       Execution::Call(isolate, proto_function, receiver, argc, argv, false));
   return *result;
 }
 }
 }  // namespace v8::internal