Unify BindState refcount management into the bound arguments.

base/bind_internal.h

 // Copyright (c) 2011 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 BASE_BIND_INTERNAL_H_
 #define BASE_BIND_INTERNAL_H_
 
 #include <stddef.h>
 
 #include <type_traits>
@@ skipping 337 matching lines @@
     // Local references to make debugger stepping easier. If in a debugger,
     // you really want to warp ahead and step through the
     // InvokeHelper<>::MakeItSo() call below.
     return InvokeHelperType::MakeItSo(
         storage->runnable_,
         Unwrap(get<bound_indices>(storage->bound_args_))...,
         CallbackForward(unbound_args)...);
   }
 };
 
+// Used to implement MakeArgsStorage.
+template <bool is_method, typename... BoundArgs>
+struct MakeArgsStorageImpl {
+  using Type = std::tuple<BoundArgs...>;
+};
+
+template <typename Obj, typename... BoundArgs>
+struct MakeArgsStorageImpl<true, Obj*, BoundArgs...> {
+  using Type = std::tuple<scoped_refptr<Obj>, BoundArgs...>;
+};
+
+// Constructs a tuple type to store BoundArgs into BindState.
+// This wraps the first argument into a scoped_refptr if |is_method| is true and
+// the first argument is a raw pointer.
+// Other arguments are adjusted for store and packed into a tuple.
+template <bool is_method, typename... BoundArgs>
+using MakeArgsStorage = typename MakeArgsStorageImpl<
+  is_method, typename std::decay<BoundArgs>::type...>::Type;
 
 // BindState<>
 //
 // This stores all the state passed into Bind() and is also where most
 // of the template resolution magic occurs.
 //
 // Runnable is the functor we are binding arguments to.
 // RunType is type of the Run() function that the Invoker<> should use.
 // Normally, this is the same as the RunType of the Runnable, but it can
 // be different if an adapter like IgnoreResult() has been used.
 //
 // BoundArgs contains the storage type for all the bound arguments.
 template <typename Runnable, typename RunType, typename... BoundArgs>
 struct BindState;
 
 template <typename Runnable,
           typename R,
           typename... Args,
           typename... BoundArgs>
 struct BindState<Runnable, R(Args...), BoundArgs...> final
     : public BindStateBase {
  private:
   using StorageType = BindState<Runnable, R(Args...), BoundArgs...>;
   using RunnableType = Runnable;
 
+  enum { is_method = HasIsMethodTag<Runnable>::value };
+
   // true_type if Runnable is a method invocation and the first bound argument
   // is a WeakPtr.
   using IsWeakCall =
-      IsWeakMethod<HasIsMethodTag<Runnable>::value, BoundArgs...>;
+      IsWeakMethod<is_method, typename std::decay<BoundArgs>::type...>;
 
   using BoundIndices = MakeIndexSequence<sizeof...(BoundArgs)>;
   using UnboundForwardArgs = DropTypeListItem<
       sizeof...(BoundArgs),
       TypeList<typename CallbackParamTraits<Args>::ForwardType...>>;
   using UnboundForwardRunType = MakeFunctionType<R, UnboundForwardArgs>;
   using InvokeHelperType = InvokeHelper<IsWeakCall::value, R, Runnable>;
 
   using UnboundArgs = DropTypeListItem<sizeof...(BoundArgs), TypeList<Args...>>;
 
  public:
   using InvokerType = Invoker<BoundIndices, StorageType,
                               InvokeHelperType, UnboundForwardRunType>;
   using UnboundRunType = MakeFunctionType<R, UnboundArgs>;
 
   template <typename... ForwardArgs>
   BindState(const Runnable& runnable, ForwardArgs&&... bound_args)
       : BindStateBase(&Destroy),
         runnable_(runnable),
-        ref_(bound_args...),
         bound_args_(std::forward<ForwardArgs>(bound_args)...) {}
 
   RunnableType runnable_;
-  MaybeScopedRefPtr<HasIsMethodTag<Runnable>::value, BoundArgs...> ref_;
-  Tuple<BoundArgs...> bound_args_;
+  MakeArgsStorage<is_method, BoundArgs...> bound_args_;
 
  private:
   ~BindState() {}
 
   static void Destroy(BindStateBase* self) {
     delete static_cast<BindState*>(self);
   }
 };
 
 }  // namespace internal
 }  // namespace base
 
 #endif  // BASE_BIND_INTERNAL_H_