Mojo: more idiomatic C++ bindings

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

Index: mojo/public/cpp/bindings/lib/callback_internal.h
diff --git a/mojo/public/cpp/bindings/lib/callback_internal.h b/mojo/public/cpp/bindings/lib/callback_internal.h
index 4802e437f2b6be2a4bec41ca7a27398175b1dcf2..f76ebef59e6c67ba12b4f13e67534be49cc3cdb7 100644
--- a/mojo/public/cpp/bindings/lib/callback_internal.h
+++ b/mojo/public/cpp/bindings/lib/callback_internal.h
@@ -5,50 +5,21 @@
 #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 {};
+class String;
 
-template <typename T>
-struct Callback_ParamTraits<T, true> {
-  typedef const T& ForwardType;
-  static const bool kIsScopedHandle = false;
-};
+namespace internal {
 
 template <typename T>
-struct Callback_ParamTraits<T, false> {
+struct Callback_ParamTraits {
   typedef T ForwardType;
-  static const bool kIsScopedHandle = false;
 };
 
-template <typename H>
-struct Callback_ParamTraits<ScopedHandleBase<H>, true> {
-  typedef ScopedHandleBase<H> ForwardType;
-  static const bool kIsScopedHandle = true;
+template <>
+struct Callback_ParamTraits<String> {
+  typedef const String& ForwardType;
 };
 
-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&
-    Callback_Forward(T& t) {
-  return t;
-}
-
-template <typename T>
-typename EnableIf<Callback_ParamTraits<T>::kIsScopedHandle, T>::type
-    Callback_Forward(T& t) {
-  return t.Pass();
-}
-
 }  // namespace internal
 }  // namespace mojo