[proxies] Implement [[Delete]].

src/objects.h

 // Copyright 2012 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.
 
 #ifndef V8_OBJECTS_H_
 #define V8_OBJECTS_H_
 
 #include <iosfwd>
 
 #include "src/allocation.h"
@@ skipping 1793 matching lines @@
   MUST_USE_RESULT static Maybe<bool> HasProperty(LookupIterator* it);
   MUST_USE_RESULT static inline Maybe<bool> HasProperty(
       Handle<JSReceiver> object, Handle<Name> name);
   MUST_USE_RESULT static inline Maybe<bool> HasOwnProperty(Handle<JSReceiver>,
                                                            Handle<Name> name);
   MUST_USE_RESULT static inline Maybe<bool> HasElement(
       Handle<JSReceiver> object, uint32_t index);
   MUST_USE_RESULT static inline Maybe<bool> HasOwnElement(
       Handle<JSReceiver> object, uint32_t index);
 
-  // Implementation of [[Delete]], ECMA-262 5th edition, section 8.12.7.
-  MUST_USE_RESULT static MaybeHandle<Object> DeletePropertyOrElement(
+  // Implementation of ES6 [[Delete]]
+  MUST_USE_RESULT static Maybe<bool> DeletePropertyOrElement(
       Handle<JSReceiver> object, Handle<Name> name,
       LanguageMode language_mode = SLOPPY);
-  MUST_USE_RESULT static MaybeHandle<Object> DeleteProperty(
+  MUST_USE_RESULT static Maybe<bool> DeleteProperty(
       Handle<JSReceiver> object, Handle<Name> name,
       LanguageMode language_mode = SLOPPY);
-  MUST_USE_RESULT static MaybeHandle<Object> DeleteProperty(
-      LookupIterator* it, LanguageMode language_mode);
-  MUST_USE_RESULT static MaybeHandle<Object> DeleteElement(
+  MUST_USE_RESULT static Maybe<bool> DeleteProperty(LookupIterator* it,
+                                                    LanguageMode language_mode);
+  MUST_USE_RESULT static Maybe<bool> DeleteElement(
       Handle<JSReceiver> object, uint32_t index,
       LanguageMode language_mode = SLOPPY);
 
   MUST_USE_RESULT static Object* DefineProperty(Isolate* isolate,
                                                 Handle<Object> object,
                                                 Handle<Object> name,
                                                 Handle<Object> attributes);
   MUST_USE_RESULT static Object* DefineProperties(Isolate* isolate,
                                                   Handle<Object> object,
                                                   Handle<Object> properties);
@@ skipping 669 matching lines @@
 
   MUST_USE_RESULT static Maybe<bool> SetPropertyWithFailedAccessCheck(
       LookupIterator* it, Handle<Object> value, ShouldThrow should_throw);
 
   // Add a property to a slow-case object.
   static void AddSlowProperty(Handle<JSObject> object,
                               Handle<Name> name,
                               Handle<Object> value,
                               PropertyAttributes attributes);
 
-  MUST_USE_RESULT static MaybeHandle<Object> DeletePropertyWithInterceptor(
+  MUST_USE_RESULT static Maybe<bool> DeletePropertyWithInterceptor(
       LookupIterator* it);
 
   bool ReferencesObjectFromElements(FixedArray* elements,
                                     ElementsKind kind,
                                     Object* object);
 
   // Return the hash table backing store or the inline stored identity hash,
   // whatever is found.
   MUST_USE_RESULT Object* GetHiddenPropertiesHashTable();
 
@@ skipping 7015 matching lines @@
 
   // ES6 9.5.5
   static bool GetOwnPropertyDescriptor(LookupIterator* it,
                                        PropertyDescriptor* desc);
 
   // ES6 9.5.6
   static bool DefineOwnProperty(Isolate* isolate, Handle<JSProxy> object,
                                 Handle<Object> key, PropertyDescriptor* desc,
                                 ShouldThrow should_throw);
 
+  // ES6 9.5.10 (when passed SLOPPY)
+  MUST_USE_RESULT static Maybe<bool> DeletePropertyOrElement(
+      Handle<JSProxy> proxy, Handle<Name> name, LanguageMode language_mode);
+
   MUST_USE_RESULT static MaybeHandle<Object> GetPropertyWithHandler(
       Handle<JSProxy> proxy,
       Handle<Object> receiver,
       Handle<Name> name);
 
   // If the handler defines an accessor property with a setter, invoke it.
   // If it defines an accessor property without a setter, or a data property
   // that is read-only, fail.  In all these cases set '*done' to true.
   // Otherwise set it to false, in which case the return value is not
   // meaningful.
@@ skipping 35 matching lines @@
 
   // Invoke a trap by name. If the trap does not exist on this's handler,
   // but derived_trap is non-NULL, invoke that instead.  May cause GC.
   MUST_USE_RESULT static MaybeHandle<Object> CallTrap(
       Handle<JSProxy> proxy, const char* name, Handle<Object> derived_trap,
       int argc, Handle<Object> args[]);
 
   MUST_USE_RESULT static Maybe<bool> HasPropertyWithHandler(
       Handle<JSProxy> proxy, Handle<Name> name);
 
-  MUST_USE_RESULT static MaybeHandle<Object> DeletePropertyWithHandler(
-      Handle<JSProxy> proxy, Handle<Name> name, LanguageMode language_mode);
-
   DISALLOW_IMPLICIT_CONSTRUCTORS(JSProxy);
 };
 
 
 class JSFunctionProxy: public JSProxy {
  public:
   // [call_trap]: The call trap.
   DECL_ACCESSORS(call_trap, JSReceiver)
 
   // [construct_trap]: The construct trap.
@@ skipping 1115 matching lines @@
     }
     return value;
   }
 };
 
 
 }  // NOLINT, false-positive due to second-order macros.
 }  // NOLINT, false-positive due to second-order macros.
 
 #endif  // V8_OBJECTS_H_