[proxies] Implement [[Delete]].

src/runtime/runtime.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_RUNTIME_RUNTIME_H_
 #define V8_RUNTIME_RUNTIME_H_
 
 #include "src/allocation.h"
 #include "src/objects.h"
 #include "src/unicode.h"
@@ skipping 1152 matching lines @@
 
   // Get the intrinsic function with the given FunctionId.
   static const Function* FunctionForId(FunctionId id);
 
   // Get the intrinsic function with the given function entry address.
   static const Function* FunctionForEntry(Address ref);
 
   // Get the runtime intrinsic function table.
   static const Function* RuntimeFunctionTable(Isolate* isolate);
 
-  MUST_USE_RESULT static MaybeHandle<Object> DeleteObjectProperty(
+  MUST_USE_RESULT static Maybe<bool> DeleteObjectProperty(
       Isolate* isolate, Handle<JSReceiver> receiver, Handle<Object> key,
       LanguageMode language_mode);
 
   MUST_USE_RESULT static MaybeHandle<Object> SetObjectProperty(
       Isolate* isolate, Handle<Object> object, Handle<Object> key,
       Handle<Object> value, LanguageMode language_mode);
 
   MUST_USE_RESULT static MaybeHandle<Object> GetObjectProperty(
       Isolate* isolate, Handle<Object> object, Handle<Object> key,
       LanguageMode language_mode = SLOPPY);
@@ skipping 78 matching lines @@
 
 class DeclareGlobalsEvalFlag : public BitField<bool, 0, 1> {};
 class DeclareGlobalsNativeFlag : public BitField<bool, 1, 1> {};
 STATIC_ASSERT(LANGUAGE_END == 3);
 class DeclareGlobalsLanguageMode : public BitField<LanguageMode, 2, 2> {};
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_RUNTIME_RUNTIME_H_