Use intrusive base hook rather than a member hook

Summary: Because MSVC is not happy about the member hook when used in complex inheritence scenarios.

Reviewed By: yfeldblum

Differential Revision: D3774513

fbshipit-source-id: 9e1ef8dd76d966de339f8486ff1a1d0ab1571849

folly/io/async/HHWheelTimer.cpp

@@ -68,7 +68,7 @@ void HHWheelTimer::Callback::cancelTimeoutImpl() {
     assert(wheel_->count_ == 0);
     wheel_->AsyncTimeout::cancelTimeout();
   }
-  hook_.unlink();
+  unlink();
   if ((-1 != bucket_) && (wheel_->buckets_[0][bucket_].empty())) {
     auto bi = makeBitIterator(wheel_->bitmap_.begin());
     *(bi + bucket_) = false;

folly/io/async/HHWheelTimer.h

@@ -66,7 +66,9 @@ class HHWheelTimer : private folly::AsyncTimeout,
   /**
    * A callback to be notified when a timeout has expired.
    */
-  class Callback {
+  class Callback
+      : public boost::intrusive::list_base_hook<
+            boost::intrusive::link_mode<boost::intrusive::auto_unlink>> {
    public:
     Callback()
       : wheel_(nullptr)
@@ -134,14 +136,8 @@ class HHWheelTimer : private folly::AsyncTimeout,
     std::chrono::milliseconds expiration_;
     int bucket_{-1};
 
-    typedef boost::intrusive::list_member_hook<
-      boost::intrusive::link_mode<boost::intrusive::auto_unlink> > ListHook;
-
-    ListHook hook_;
-
     typedef boost::intrusive::list<
       Callback,
-      boost::intrusive::member_hook<Callback, ListHook, &Callback::hook_>,
       boost::intrusive::constant_time_size<false> > List;
 
     std::shared_ptr<RequestContext> context_;