Back out D14608368 to HHWheelTimerBase

Summary:
Back out D14608368 "HHWheelTimerBase: use different DEFAULT_TICK_INTERVAL values for milliseconds and microseconds".

The change being backed out breaks the MSVC build; backing it out should restore the MSVC build.

Fixes #1087.

Differential Revision: D14638652

fbshipit-source-id: b06b2934771adeff7a49c54b33da84a5bc973e66

folly/io/async/HHWheelTimer.cpp

@@ -40,15 +40,8 @@ namespace folly {
  * start showing up in cpu perf.  Also, it might not be possible to set
  * tick interval less than 10ms on older kernels.
  */
-template <>
-int HHWheelTimerBase<std::chrono::milliseconds>::DEFAULT_TICK_INTERVAL = 10;
-
-/*
- * An interval of 200usec will give us 200usec * WHEEL_SIZE^WHEEL_BUCKETS
- * for the largest timeout possible, or about 9 days.
- */
-template <>
-int HHWheelTimerBase<std::chrono::microseconds>::DEFAULT_TICK_INTERVAL = 200;
+template <class Duration>
+int HHWheelTimerBase<Duration>::DEFAULT_TICK_INTERVAL = 10;
 
 template <class Duration>
 HHWheelTimerBase<Duration>::Callback::Callback() {}

folly/io/async/HHWheelTimer.h

@@ -343,16 +343,11 @@ class HHWheelTimerBase : private folly::AsyncTimeout,
   }
 };
 
-// std::chrono::milliseconds
-template <>
-int HHWheelTimerBase<std::chrono::milliseconds>::DEFAULT_TICK_INTERVAL;
 using HHWheelTimer = HHWheelTimerBase<std::chrono::milliseconds>;
 extern template class HHWheelTimerBase<std::chrono::milliseconds>;
 
 // std::chrono::microseconds
 template <>
-int HHWheelTimerBase<std::chrono::microseconds>::DEFAULT_TICK_INTERVAL;
-template <>
 void HHWheelTimerBase<std::chrono::microseconds>::scheduleTimeoutInternal(
     std::chrono::microseconds timeout);