Make integer indexed properties ("elements") work for proxies.

src/objects-inl.h

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 4311 matching lines @@
                                     DONT_ENUM,
                                     kNonStrictMode);
 }
 
 
 bool JSObject::HasHiddenProperties() {
   return !GetHiddenProperties(OMIT_CREATION)->ToObjectChecked()->IsUndefined();
 }
 
 
-bool JSObject::HasElement(uint32_t index) {
-  return HasElementWithReceiver(this, index);
+bool JSReceiver::HasElement(uint32_t index) {
+  if (IsJSProxy()) {
+    return JSProxy::cast(this)->HasElementWithHandler(index);
+  }
+  return JSObject::cast(this)->HasElementWithReceiver(this, index);
 }
 
 
 bool AccessorInfo::all_can_read() {
   return BooleanBit::get(flag(), kAllCanReadBit);
 }
 
 
 void AccessorInfo::set_all_can_read(bool value) {
   set_flag(BooleanBit::set(flag(), kAllCanReadBit, value));
@@ skipping 274 matching lines @@
 #undef WRITE_INT_FIELD
 #undef READ_SHORT_FIELD
 #undef WRITE_SHORT_FIELD
 #undef READ_BYTE_FIELD
 #undef WRITE_BYTE_FIELD
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_INL_H_