[proxies] Implement [[Delete]].

src/runtime/runtime-object.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/runtime/runtime-utils.h"
 
 #include "src/arguments.h"
 #include "src/bootstrapper.h"
 #include "src/debug/debug.h"
 #include "src/isolate-inl.h"
@@ skipping 100 matching lines @@
           String::Flatten(str)->Get(index));
     }
   }
 
   // Fall back to GetObjectProperty.
   return Runtime::GetObjectProperty(isolate, receiver_obj, key_obj,
                                     language_mode);
 }
 
 
-MaybeHandle<Object> Runtime::DeleteObjectProperty(Isolate* isolate,
-                                                  Handle<JSReceiver> receiver,
-                                                  Handle<Object> key,
-                                                  LanguageMode language_mode) {
+Maybe<bool> Runtime::DeleteObjectProperty(Isolate* isolate,
+                                          Handle<JSReceiver> receiver,
+                                          Handle<Object> key,
+                                          LanguageMode language_mode) {
   bool success = false;
   LookupIterator it = LookupIterator::PropertyOrElement(
       isolate, receiver, key, &success, LookupIterator::HIDDEN);
-  if (!success) return MaybeHandle<Object>();
+  if (!success) return Nothing<bool>();
 
   return JSReceiver::DeleteProperty(&it, language_mode);
 }
 
 
 MaybeHandle<Object> Runtime::SetObjectProperty(Isolate* isolate,
                                                Handle<Object> object,
                                                Handle<Object> key,
                                                Handle<Object> value,
                                                LanguageMode language_mode) {
@@ skipping 472 matching lines @@
 namespace {
 
 // ES6 section 12.5.4.
 Object* DeleteProperty(Isolate* isolate, Handle<Object> object,
                        Handle<Object> key, LanguageMode language_mode) {
   Handle<JSReceiver> receiver;
   if (!JSReceiver::ToObject(isolate, object).ToHandle(&receiver)) {
     THROW_NEW_ERROR_RETURN_FAILURE(
         isolate, NewTypeError(MessageTemplate::kUndefinedOrNullToObject));
   }
-  Handle<Object> result;
-  ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
-      isolate, result,
-      Runtime::DeleteObjectProperty(isolate, receiver, key, language_mode));
-  return *result;
+  Maybe<bool> result =
+      Runtime::DeleteObjectProperty(isolate, receiver, key, language_mode);
+  MAYBE_RETURN(result, isolate->heap()->exception());
+  return isolate->heap()->ToBoolean(result.FromJust());
 }
 
 }  // namespace
 
 
 RUNTIME_FUNCTION(Runtime_DeleteProperty_Sloppy) {
   HandleScope scope(isolate);
   DCHECK_EQ(2, args.length());
   CONVERT_ARG_HANDLE_CHECKED(Object, object, 0);
   CONVERT_ARG_HANDLE_CHECKED(Object, key, 1);
@@ skipping 947 matching lines @@
 
 RUNTIME_FUNCTION(Runtime_ObjectDefineProperties) {
   HandleScope scope(isolate);
   DCHECK(args.length() == 2);
   CONVERT_ARG_HANDLE_CHECKED(Object, o, 0);
   CONVERT_ARG_HANDLE_CHECKED(Object, properties, 1);
   return JSReceiver::DefineProperties(isolate, o, properties);
 }
 }  // namespace internal
 }  // namespace v8