Mojo: more idiomatic C++ bindings

mojo/public/cpp/bindings/lib/callback_internal.h

 // Copyright 2014 The Chromium 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 MOJO_PUBLIC_CPP_BINDINGS_LIB_CALLBACK_INTERNAL_H_
 #define MOJO_PUBLIC_CPP_BINDINGS_LIB_CALLBACK_INTERNAL_H_
 
 #include "mojo/public/cpp/bindings/lib/bindings_internal.h"
 
 namespace mojo {
 namespace internal {
 
 template <typename T, bool is_object_type = TypeTraits<T>::kIsObject>
 struct Callback_ParamTraits {};
 
 template <typename T>
 struct Callback_ParamTraits<T, true> {
-  typedef const T& ForwardType;
-  static const bool kIsScopedHandle = false;
+  typedef T ForwardType;
+  static const bool kIsMoveOnlyType = true;
 };
 
 template <typename T>
 struct Callback_ParamTraits<T, false> {
   typedef T ForwardType;
-  static const bool kIsScopedHandle = false;
+  static const bool kIsMoveOnlyType = false;
 };
 
 template <typename H>
 struct Callback_ParamTraits<ScopedHandleBase<H>, true> {
   typedef ScopedHandleBase<H> ForwardType;
-  static const bool kIsScopedHandle = true;
+  static const bool kIsMoveOnlyType = true;
 };
 
 template<bool B, typename T = void>
 struct EnableIf {};
 
 template<typename T>
 struct EnableIf<true, T> { typedef T type; };
 
 template <typename T>
-typename EnableIf<!Callback_ParamTraits<T>::kIsScopedHandle, T>::type&
+typename EnableIf<!Callback_ParamTraits<T>::kIsMoveOnlyType, T>::type&
     Callback_Forward(T& t) {
   return t;
 }
 
 template <typename T>
-typename EnableIf<Callback_ParamTraits<T>::kIsScopedHandle, T>::type
+typename EnableIf<Callback_ParamTraits<T>::kIsMoveOnlyType, T>::type
     Callback_Forward(T& t) {
   return t.Pass();
 }
 
 }  // namespace internal
 }  // namespace mojo
 
 #endif  // MOJO_PUBLIC_CPP_BINDINGS_LIB_CALLBACK_INTERNAL_H_