Make Object::IsFoo const.

src/api.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_API_H_
 #define V8_API_H_
 
 #include "src/v8.h"
 
 #include "include/v8-testing.h"
@@ skipping 352 matching lines @@
 #undef MAKE_TO_LOCAL
 
 
 // Implementations of OpenHandle
 
 #define MAKE_OPEN_HANDLE(From, To)                                          \
   v8::internal::Handle<v8::internal::To> Utils::OpenHandle(                 \
     const v8::From* that, bool allow_empty_handle) {                        \
     EXTRA_CHECK(allow_empty_handle || that != NULL);                        \
     EXTRA_CHECK(that == NULL ||                                             \
-        (*reinterpret_cast<v8::internal::Object**>(                         \
-            const_cast<v8::From*>(that)))->Is##To());                       \
+        (*reinterpret_cast<v8::internal::Object* const*>(that))->Is##To()); \
     return v8::internal::Handle<v8::internal::To>(                          \
         reinterpret_cast<v8::internal::To**>(const_cast<v8::From*>(that))); \
   }
 
 OPEN_HANDLE_LIST(MAKE_OPEN_HANDLE)
 
 #undef MAKE_OPEN_HANDLE
 #undef OPEN_HANDLE_LIST
 
 
@@ skipping 301 matching lines @@
     stress_type_ = stress_type;
   }
 
  private:
   static v8::Testing::StressType stress_type_;
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_API_H_