Remove FiberManagerFuture.h as it's dead

Summary: All functions in this file are defined in `folly/fibers/FiberManager-inl.h`. There are no remaining references to this file.

Reviewed By: yfeldblum

Differential Revision: D5163160

fbshipit-source-id: 2fcb782a4de78f5c067610c876d0cf98f3b69e63

folly/fibers/FiberManagerFuture.h

-/*
- * Copyright 2017 Facebook, Inc.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *   http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-#pragma once
-
-#include <folly/futures/Promise.h>
-
-namespace folly {
-namespace fibers {
-
-template <typename F>
-auto FiberManager::addTaskFuture(F&& func) -> folly::Future<
-    typename folly::Unit::Lift<typename std::result_of<F()>::type>::type> {
-  using T = typename std::result_of<F()>::type;
-  using FutureT = typename folly::Unit::Lift<T>::type;
-
-  folly::Promise<FutureT> p;
-  auto f = p.getFuture();
-  addTaskFinally(
-      [func = std::forward<F>(func)]() mutable { return func(); },
-      [p = std::move(p)](folly::Try<T> && t) mutable {
-        p.setTry(std::move(t));
-      });
-  return f;
-}
-
-template <typename F>
-auto FiberManager::addTaskRemoteFuture(F&& func) -> folly::Future<
-    typename folly::Unit::Lift<typename std::result_of<F()>::type>::type> {
-  folly::Promise<
-      typename folly::Unit::Lift<typename std::result_of<F()>::type>::type>
-      p;
-  auto f = p.getFuture();
-  addTaskRemote(
-      [ p = std::move(p), func = std::forward<F>(func), this ]() mutable {
-        auto t = folly::makeTryWith(std::forward<F>(func));
-        runInMainContext([&]() { p.setTry(std::move(t)); });
-      });
-  return f;
-}
-}
-}