Make Object::IsFoo const.

include/v8.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.
 
 /** \mainpage V8 API Reference Guide
  *
  * V8 is Google's open source JavaScript engine.
  *
  * This set of documents provides reference material generated from the
  * V8 header file, include/v8.h.
@@ skipping 6196 matching lines @@
   typedef internal::Internals I;
   I::CheckInitialized(isolate);
   S* slot = I::GetRoot(isolate, I::kEmptyStringRootIndex);
   return Local<String>(reinterpret_cast<String*>(slot));
 }
 
 
 String::ExternalStringResource* String::GetExternalStringResource() const {
   typedef internal::Object O;
   typedef internal::Internals I;
-  O* obj = *reinterpret_cast<O**>(const_cast<String*>(this));
+  O* obj = *reinterpret_cast<O* const*>(this);
   String::ExternalStringResource* result;
   if (I::IsExternalTwoByteString(I::GetInstanceType(obj))) {
     void* value = I::ReadField<void*>(obj, I::kStringResourceOffset);
     result = reinterpret_cast<String::ExternalStringResource*>(value);
   } else {
     result = NULL;
   }
 #ifdef V8_ENABLE_CHECKS
   VerifyExternalStringResource(result);
 #endif
   return result;
 }
 
 
 String::ExternalStringResourceBase* String::GetExternalStringResourceBase(
     String::Encoding* encoding_out) const {
   typedef internal::Object O;
   typedef internal::Internals I;
-  O* obj = *reinterpret_cast<O**>(const_cast<String*>(this));
+  O* obj = *reinterpret_cast<O* const*>(this);
   int type = I::GetInstanceType(obj) & I::kFullStringRepresentationMask;
   *encoding_out = static_cast<Encoding>(type & I::kStringEncodingMask);
   ExternalStringResourceBase* resource = NULL;
   if (type == I::kExternalAsciiRepresentationTag ||
       type == I::kExternalTwoByteRepresentationTag) {
     void* value = I::ReadField<void*>(obj, I::kStringResourceOffset);
     resource = static_cast<ExternalStringResourceBase*>(value);
   }
 #ifdef V8_ENABLE_CHECKS
     VerifyExternalStringResourceBase(resource, *encoding_out);
 #endif
   return resource;
 }
 
 
 bool Value::IsUndefined() const {
 #ifdef V8_ENABLE_CHECKS
   return FullIsUndefined();
 #else
   return QuickIsUndefined();
 #endif
 }
 
 bool Value::QuickIsUndefined() const {
   typedef internal::Object O;
   typedef internal::Internals I;
-  O* obj = *reinterpret_cast<O**>(const_cast<Value*>(this));
+  O* obj = *reinterpret_cast<O* const*>(this);
   if (!I::HasHeapObjectTag(obj)) return false;
   if (I::GetInstanceType(obj) != I::kOddballType) return false;
   return (I::GetOddballKind(obj) == I::kUndefinedOddballKind);
 }
 
 
 bool Value::IsNull() const {
 #ifdef V8_ENABLE_CHECKS
   return FullIsNull();
 #else
   return QuickIsNull();
 #endif
 }
 
 bool Value::QuickIsNull() const {
   typedef internal::Object O;
   typedef internal::Internals I;
-  O* obj = *reinterpret_cast<O**>(const_cast<Value*>(this));
+  O* obj = *reinterpret_cast<O* const*>(this);
   if (!I::HasHeapObjectTag(obj)) return false;
   if (I::GetInstanceType(obj) != I::kOddballType) return false;
   return (I::GetOddballKind(obj) == I::kNullOddballKind);
 }
 
 
 bool Value::IsString() const {
 #ifdef V8_ENABLE_CHECKS
   return FullIsString();
 #else
   return QuickIsString();
 #endif
 }
 
 bool Value::QuickIsString() const {
   typedef internal::Object O;
   typedef internal::Internals I;
-  O* obj = *reinterpret_cast<O**>(const_cast<Value*>(this));
+  O* obj = *reinterpret_cast<O* const*>(this);
   if (!I::HasHeapObjectTag(obj)) return false;
   return (I::GetInstanceType(obj) < I::kFirstNonstringType);
 }
 
 
 template <class T> Value* Value::Cast(T* value) {
   return static_cast<Value*>(value);
 }
 
 
@@ skipping 391 matching lines @@
  */
 
 
 }  // namespace v8
 
 
 #undef TYPE_CHECK
 
 
 #endif  // V8_H_