first step to remove unsafe handles

src/api.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 273 matching lines @@
 v8::internal::Handle<T> v8::internal::Handle<T>::EscapeFrom(
     v8::HandleScope* scope) {
   v8::internal::Handle<T> handle;
   if (!is_null()) {
     handle = *this;
   }
   return Utils::OpenHandle(*scope->Close(Utils::ToLocal(handle)), true);
 }
 
 
+class InternalHandleHelper {
+ public:
+  template<class From, class To>
+  static inline Local<To> Convert(v8::internal::Handle<From> obj) {
+    return Local<To>(reinterpret_cast<To*>(obj.location()));
+  }
+};
+
+
 // Implementations of ToLocal
 
 #define MAKE_TO_LOCAL(Name, From, To)                                       \
   Local<v8::To> Utils::Name(v8::internal::Handle<v8::internal::From> obj) { \
     ASSERT(obj.is_null() || !obj->IsTheHole());                             \
-    return Local<To>(reinterpret_cast<To*>(obj.location()));                \
+    return InternalHandleHelper::Convert<v8::internal::From, v8::To>(obj);  \
   }
 
 
 #define MAKE_TO_LOCAL_TYPED_ARRAY(TypedArray, typeConst)                    \
   Local<v8::TypedArray> Utils::ToLocal##TypedArray(                         \
       v8::internal::Handle<v8::internal::JSTypedArray> obj) {               \
     ASSERT(obj.is_null() || !obj->IsTheHole());                             \
     ASSERT(obj->type() == typeConst);                                       \
-    return Local<v8::TypedArray>(                                           \
-        reinterpret_cast<v8::TypedArray*>(obj.location()));                 \
+    return InternalHandleHelper::                                           \
+        Convert<v8::internal::JSTypedArray, v8::TypedArray>(obj);           \
   }
 
 
 MAKE_TO_LOCAL(ToLocal, Context, Context)
 MAKE_TO_LOCAL(ToLocal, Object, Value)
 MAKE_TO_LOCAL(ToLocal, JSFunction, Function)
 MAKE_TO_LOCAL(ToLocal, String, String)
 MAKE_TO_LOCAL(ToLocal, Symbol, Symbol)
 MAKE_TO_LOCAL(ToLocal, JSRegExp, RegExp)
 MAKE_TO_LOCAL(ToLocal, JSObject, Object)
@@ skipping 332 matching lines @@
     stress_type_ = stress_type;
   }
 
  private:
   static v8::Testing::StressType stress_type_;
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_API_H_