Implement `in' for proxies.

src/objects.cc

Index: src/objects.cc
diff --git a/src/objects.cc b/src/objects.cc
index 26ab64552fc344fff7be569d3f43b365650c4d6f..b1d5f1453c1a6aa62e760db7df455dc3a6aa1da2 100644
--- a/src/objects.cc
+++ b/src/objects.cc
@@ -2196,6 +2196,31 @@ MaybeObject* JSReceiver::SetProperty(LookupResult* result,
 }
 
 
+bool JSProxy::HasPropertyWithHandler(String* name_raw) {
+  Isolate* isolate = GetIsolate();
+  HandleScope scope(isolate);
+  Handle<Object> receiver(this);
+  Handle<Object> name(name_raw);
+  Handle<Object> handler(this->handler());
+
+  // Extract trap function.
+  Handle<String> trap_name = isolate->factory()->LookupAsciiSymbol("has");
+  Handle<Object> trap(v8::internal::GetProperty(handler, trap_name));
+  if (trap->IsUndefined()) {
+    trap = isolate->derived_has_trap();
+  }
+
+  // Call trap function.
+  Object** args[] = { name.location() };
+  bool has_exception;
+  Handle<Object> result =
+      Execution::Call(trap, handler, ARRAY_SIZE(args), args, &has_exception);
+  if (has_exception) return Failure::Exception();
+
+  return result->ToBoolean()->IsTrue();
+}
+
+
 MUST_USE_RESULT MaybeObject* JSProxy::SetPropertyWithHandler(
     String* name_raw,
     Object* value_raw,
@@ -2301,6 +2326,18 @@ MUST_USE_RESULT PropertyAttributes JSProxy::GetPropertyAttributeWithHandler(
 }
 
 
+void JSProxy::Fix() {
+  Isolate* isolate = GetIsolate();
+  HandleScope scope(isolate);
+  Handle<JSProxy> self(this);
+
+  isolate->factory()->BecomeJSObject(self);
+  ASSERT(IsJSObject());
+  // TODO(rossberg): recognize function proxies.
+}
+
+
+
 MaybeObject* JSObject::SetPropertyForResult(LookupResult* result,
                                             String* name,
                                             Object* value,