[proxies] Implement Proxy.revocable.

src/objects-inl.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.
 //
 // Review notes:
 //
 // - The use of macros in these inline functions may seem superfluous
 // but it is absolutely needed to make sure gcc generates optimal
 // code. gcc is not happy when attempting to inline too deep.
 //
@@ skipping 6319 matching lines @@
   set_literals_or_bindings(bindings);
 }
 
 
 int JSFunction::NumberOfLiterals() {
   DCHECK(!shared()->bound());
   return literals()->length();
 }
 
 
-ACCESSORS(JSProxy, target, Object, kTargetOffset)
 ACCESSORS(JSProxy, handler, Object, kHandlerOffset)
+ACCESSORS(JSProxy, target, JSReceiver, kTargetOffset)
 ACCESSORS(JSProxy, hash, Object, kHashOffset)
 
+bool JSProxy::IsRevoked() const { return !handler()->IsJSReceiver(); }
+
 ACCESSORS(JSFunctionProxy, call_trap, JSReceiver, kCallTrapOffset)
 ACCESSORS(JSFunctionProxy, construct_trap, Object, kConstructTrapOffset)
 
 
 ACCESSORS(JSCollection, table, Object, kTableOffset)
 
 
 #define ORDERED_HASH_TABLE_ITERATOR_ACCESSORS(name, type, offset)    \
   template<class Derived, class TableType>                           \
   type* OrderedHashTableIterator<Derived, TableType>::name() const { \
@@ skipping 1517 matching lines @@
 #undef WRITE_INT64_FIELD
 #undef READ_BYTE_FIELD
 #undef WRITE_BYTE_FIELD
 #undef NOBARRIER_READ_BYTE_FIELD
 #undef NOBARRIER_WRITE_BYTE_FIELD
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_OBJECTS_INL_H_