Implement function proxies (except for their use as constructors).

src/factory.cc

Index: src/factory.cc
diff --git a/src/factory.cc b/src/factory.cc
index 05dd5c96619ea25d61feb38d8f54a9834b61f7e7..638e6aca9e91b06ff226cb9b7b5974529945743f 100644
--- a/src/factory.cc
+++ b/src/factory.cc
@@ -900,10 +900,19 @@ Handle<JSProxy> Factory::NewJSProxy(Handle<Object> handler,
 }
 
 
-void Factory::BecomeJSObject(Handle<JSProxy> object) {
+void Factory::BecomeJSObject(Handle<JSReceiver> object) {
   CALL_HEAP_FUNCTION_VOID(
       isolate(),
-      isolate()->heap()->ReinitializeJSProxyAsJSObject(*object));
+      isolate()->heap()->ReinitializeJSReceiver(
+          *object, JS_OBJECT_TYPE, JSObject::kHeaderSize));
+}
+
+
+void Factory::BecomeJSFunction(Handle<JSReceiver> object) {
+  CALL_HEAP_FUNCTION_VOID(
+      isolate(),
+      isolate()->heap()->ReinitializeJSReceiver(
+          *object, JS_FUNCTION_TYPE, JSFunction::kSize));
 }