Remove overloads for Callback in bind_helpers.h

base/bind_helpers.h

Index: base/bind_helpers.h
diff --git a/base/bind_helpers.h b/base/bind_helpers.h
index d86393bec05676d942bd13f3df72a08ce828d53a..093f5dcfeeead6af87659347517a398472eb3cf3 100644
--- a/base/bind_helpers.h
+++ b/base/bind_helpers.h
@@ -344,18 +344,11 @@ class RetainedRefWrapper {
 
 template <typename T>
 struct IgnoreResultHelper {
-  explicit IgnoreResultHelper(T functor) : functor_(functor) {}
+  explicit IgnoreResultHelper(T functor) : functor_(std::move(functor)) {}

[Yuta Kitamura, 2016/06/29 00:07:55]

Do you expect |T| to be something like Callback<T>? Is
there any other thing?

[tzik, 2016/06/29 02:49:08]

T is a Functor. That can be Callback<>, function pointers, method pointers, or
IgnoreResult<>.

 
   T functor_;
 };
 
-template <typename T>
-struct IgnoreResultHelper<Callback<T> > {
-  explicit IgnoreResultHelper(const Callback<T>& functor) : functor_(functor) {}
-
-  const Callback<T>& functor_;
-};
-
 // An alternate implementation is to avoid the destructive copy, and instead
 // specialize ParamTraits<> for OwnedWrapper<> to change the StorageType to
 // a class that is essentially a std::unique_ptr<>.
@@ -421,8 +414,8 @@ class PassedWrapper {
 
 // Unwrap the stored parameters for the wrappers above.
 template <typename T>
-const T& Unwrap(const T& o) {
-  return o;
+T&& Unwrap(T&& o) {

[Yuta Kitamura, 2016/06/29 00:07:55]

aside: If the argument can be an rvalue reference, WTF's
PassedWrapper's mutable can be removed by using rref?

[tzik, 2016/06/29 02:49:08]

No. The constness of the internal storage is from Invoker::Run(), which uses
const StorageType.

+  return std::forward<T>(o);
 }
 
 template <typename T>
@@ -611,13 +604,7 @@ static inline internal::PassedWrapper<T> Passed(T* scoper) {
 
 template <typename T>
 static inline internal::IgnoreResultHelper<T> IgnoreResult(T data) {
-  return internal::IgnoreResultHelper<T>(data);
-}
-
-template <typename T>
-static inline internal::IgnoreResultHelper<Callback<T> >
-IgnoreResult(const Callback<T>& data) {
-  return internal::IgnoreResultHelper<Callback<T> >(data);
+  return internal::IgnoreResultHelper<T>(std::move(data));
 }
 
 BASE_EXPORT void DoNothing();