Tighten OpenHandle's extra checks.

include/v8.h

 // Copyright 2012 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 2504 matching lines @@
 
 /**
  * The information passed to a property callback about the context
  * of the property access.
  */
 template<typename T>
 class PropertyCallbackInfo {
  public:
   V8_INLINE Isolate* GetIsolate() const;
   V8_INLINE Local<Value> Data() const;
-  V8_INLINE Local<Object> This() const;
+  V8_INLINE Local<Value> This() const;
   V8_INLINE Local<Object> Holder() const;
   V8_INLINE ReturnValue<T> GetReturnValue() const;
   // This shouldn't be public, but the arm compiler needs it.
   static const int kArgsLength = 6;
 
  protected:
   friend class MacroAssembler;
   friend class internal::PropertyCallbackArguments;
   friend class internal::CustomArguments<PropertyCallbackInfo>;
   static const int kHolderIndex = 0;
@@ skipping 3952 matching lines @@
 }
 
 
 template<typename T>
 Local<Value> PropertyCallbackInfo<T>::Data() const {
   return Local<Value>(reinterpret_cast<Value*>(&args_[kDataIndex]));
 }
 
 
 template<typename T>
-Local<Object> PropertyCallbackInfo<T>::This() const {
-  return Local<Object>(reinterpret_cast<Object*>(&args_[kThisIndex]));
+Local<Value> PropertyCallbackInfo<T>::This() const {
+  return Local<Value>(reinterpret_cast<Value*>(&args_[kThisIndex]));
 }
 
 
 template<typename T>
 Local<Object> PropertyCallbackInfo<T>::Holder() const {
   return Local<Object>(reinterpret_cast<Object*>(&args_[kHolderIndex]));
 }
 
 
 template<typename T>
@@ skipping 120 matching lines @@
  */
 
 
 }  // namespace v8
 
 
 #undef TYPE_CHECK
 
 
 #endif  // V8_H_