[es6] Introduce spec compliant IsConstructor.

src/factory.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 "src/factory.h"
 
 #include "src/allocation-site-scopes.h"
 #include "src/base/bits.h"
 #include "src/bootstrapper.h"
 #include "src/conversions.h"
@@ skipping 1912 matching lines @@
 Handle<JSProxy> Factory::NewJSFunctionProxy(Handle<Object> handler,
                                             Handle<JSReceiver> call_trap,
                                             Handle<Object> construct_trap,
                                             Handle<Object> prototype) {
   // Allocate map.
   // TODO(rossberg): Once we optimize proxies, think about a scheme to share
   // maps. Will probably depend on the identity of the handler object, too.
   Handle<Map> map = NewMap(JS_FUNCTION_PROXY_TYPE, JSFunctionProxy::kSize);
   Map::SetPrototype(map, prototype);
   map->set_is_callable();
+  map->set_is_constructor(construct_trap->IsCallable());
 
   // Allocate the proxy object.
   Handle<JSFunctionProxy> result = New<JSFunctionProxy>(map, NEW_SPACE);
   result->InitializeBody(map->instance_size(), Smi::FromInt(0));
   result->set_handler(*handler);
   result->set_hash(*undefined_value(), SKIP_WRITE_BARRIER);
   result->set_call_trap(*call_trap);
   result->set_construct_trap(*construct_trap);
   return result;
 }
@@ skipping 41 matching lines @@
   // Reinitialize the object from the constructor map.
   heap->InitializeJSObjectFromMap(*jsobj, *properties, *map);
 
   // The current native context is used to set up certain bits.
   // TODO(adamk): Using the current context seems wrong, it should be whatever
   // context the JSProxy originated in. But that context isn't stored anywhere.
   Handle<Context> context(isolate()->native_context());
 
   // Functions require some minimal initialization.
   if (type == JS_FUNCTION_TYPE) {
-    map->set_function_with_prototype(true);
+    map->set_is_constructor(true);
     map->set_is_callable();
     Handle<JSFunction> js_function = Handle<JSFunction>::cast(proxy);
     InitializeFunction(js_function, shared.ToHandleChecked(), context);
   } else {
     // Provide JSObjects with a constructor.
     map->SetConstructor(context->object_function());
   }
 }
 
 
@@ skipping 368 matching lines @@
 }
 
 
 Handle<Object> Factory::ToBoolean(bool value) {
   return value ? true_value() : false_value();
 }
 
 
 }  // namespace internal
 }  // namespace v8