Revert 154885 - Extend base::Callback to 8 arguments.

base/callback.h

Index: base/callback.h
===================================================================
--- base/callback.h	(revision 154900)
+++ base/callback.h	(working copy)
@@ -748,70 +748,7 @@
 
 };
 
-template <typename R, typename A1, typename A2, typename A3, typename A4,
-    typename A5, typename A6, typename A7, typename A8>
-class Callback<R(A1, A2, A3, A4, A5, A6, A7, A8)>
-    : public internal::CallbackBase {
- public:
-  typedef R(RunType)(A1, A2, A3, A4, A5, A6, A7, A8);
 
-  Callback() : CallbackBase(NULL) { }
-
-  // Note that this constructor CANNOT be explicit, and that Bind() CANNOT
-  // return the exact Callback<> type.  See base/bind.h for details.
-  template <typename Runnable, typename BindRunType, typename BoundArgsType>
-  Callback(internal::BindState<Runnable, BindRunType,
-           BoundArgsType>* bind_state)
-      : CallbackBase(bind_state) {
-
-    // Force the assignment to a local variable of PolymorphicInvoke
-    // so the compiler will typecheck that the passed in Run() method has
-    // the correct type.
-    PolymorphicInvoke invoke_func =
-        &internal::BindState<Runnable, BindRunType, BoundArgsType>
-            ::InvokerType::Run;
-    polymorphic_invoke_ = reinterpret_cast<InvokeFuncStorage>(invoke_func);
-  }
-
-  bool Equals(const Callback& other) const {
-    return CallbackBase::Equals(other);
-  }
-
-  R Run(typename internal::CallbackParamTraits<A1>::ForwardType a1,
-        typename internal::CallbackParamTraits<A2>::ForwardType a2,
-        typename internal::CallbackParamTraits<A3>::ForwardType a3,
-        typename internal::CallbackParamTraits<A4>::ForwardType a4,
-        typename internal::CallbackParamTraits<A5>::ForwardType a5,
-        typename internal::CallbackParamTraits<A6>::ForwardType a6,
-        typename internal::CallbackParamTraits<A7>::ForwardType a7,
-        typename internal::CallbackParamTraits<A8>::ForwardType a8) const {
-    PolymorphicInvoke f =
-        reinterpret_cast<PolymorphicInvoke>(polymorphic_invoke_);
-
-    return f(bind_state_.get(), internal::CallbackForward(a1),
-             internal::CallbackForward(a2),
-             internal::CallbackForward(a3),
-             internal::CallbackForward(a4),
-             internal::CallbackForward(a5),
-             internal::CallbackForward(a6),
-             internal::CallbackForward(a7),
-             internal::CallbackForward(a8));
-  }
-
- private:
-  typedef R(*PolymorphicInvoke)(
-      internal::BindStateBase*,
-          typename internal::CallbackParamTraits<A1>::ForwardType,
-          typename internal::CallbackParamTraits<A2>::ForwardType,
-          typename internal::CallbackParamTraits<A3>::ForwardType,
-          typename internal::CallbackParamTraits<A4>::ForwardType,
-          typename internal::CallbackParamTraits<A5>::ForwardType,
-          typename internal::CallbackParamTraits<A6>::ForwardType,
-          typename internal::CallbackParamTraits<A7>::ForwardType,
-          typename internal::CallbackParamTraits<A8>::ForwardType);
-
-};
-
 // Syntactic sugar to make Callbacks<void(void)> easier to declare since it
 // will be used in a lot of APIs with delayed execution.
 typedef Callback<void(void)> Closure;