chore(3p/abseil_cpp): unvendor abseil_cpp r/3786

we weren't actually using these sources anymore, okay?

Change-Id: If701571d9716de308d3512e1eb22c35db0877a66
Reviewed-on: https://cl.tvl.fyi/c/depot/+/5248
Tested-by: BuildkiteCI
Reviewed-by: grfn <grfn@gws.fyi>
Autosubmit: tazjin <tazjin@tvl.su>

9 files changed, 0 insertions, 1319 deletions

diff --git a/third_party/abseil_cpp/absl/functional/BUILD.bazel b/third_party/abseil_cpp/absl/functional/BUILD.bazel
deleted file mode 100644
index ebd9b99b782f..000000000000
--- a/third_party/abseil_cpp/absl/functional/BUILD.bazel
+++ /dev/null
@@ -1,93 +0,0 @@
-#
-# Copyright 2019 The Abseil Authors.
-#
-# 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
-#
-#      https://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.
-#
-
-load("@rules_cc//cc:defs.bzl", "cc_library", "cc_test")
-load(
-    "//absl:copts/configure_copts.bzl",
-    "ABSL_DEFAULT_COPTS",
-    "ABSL_DEFAULT_LINKOPTS",
-    "ABSL_TEST_COPTS",
-)
-
-package(default_visibility = ["//visibility:public"])
-
-licenses(["notice"])
-
-cc_library(
-    name = "bind_front",
-    srcs = ["internal/front_binder.h"],
-    hdrs = ["bind_front.h"],
-    copts = ABSL_DEFAULT_COPTS,
-    linkopts = ABSL_DEFAULT_LINKOPTS,
-    deps = [
-        "//absl/base:base_internal",
-        "//absl/container:compressed_tuple",
-        "//absl/meta:type_traits",
-        "//absl/utility",
-    ],
-)
-
-cc_test(
-    name = "bind_front_test",
-    srcs = ["bind_front_test.cc"],
-    copts = ABSL_TEST_COPTS,
-    linkopts = ABSL_DEFAULT_LINKOPTS,
-    deps = [
-        ":bind_front",
-        "//absl/memory",
-        "@com_google_googletest//:gtest_main",
-    ],
-)
-
-cc_library(
-    name = "function_ref",
-    srcs = ["internal/function_ref.h"],
-    hdrs = ["function_ref.h"],
-    copts = ABSL_DEFAULT_COPTS,
-    linkopts = ABSL_DEFAULT_LINKOPTS,
-    deps = [
-        "//absl/base:base_internal",
-        "//absl/meta:type_traits",
-    ],
-)
-
-cc_test(
-    name = "function_ref_test",
-    size = "small",
-    srcs = ["function_ref_test.cc"],
-    copts = ABSL_TEST_COPTS,
-    deps = [
-        ":function_ref",
-        "//absl/container:test_instance_tracker",
-        "//absl/memory",
-        "@com_google_googletest//:gtest_main",
-    ],
-)
-
-cc_test(
-    name = "function_ref_benchmark",
-    srcs = [
-        "function_ref_benchmark.cc",
-    ],
-    copts = ABSL_TEST_COPTS,
-    tags = ["benchmark"],
-    visibility = ["//visibility:private"],
-    deps = [
-        ":function_ref",
-        "//absl/base:core_headers",
-        "@com_github_google_benchmark//:benchmark_main",
-    ],
-)
diff --git a/third_party/abseil_cpp/absl/functional/CMakeLists.txt b/third_party/abseil_cpp/absl/functional/CMakeLists.txt
deleted file mode 100644
index cda914f2cd53..000000000000
--- a/third_party/abseil_cpp/absl/functional/CMakeLists.txt
+++ /dev/null
@@ -1,72 +0,0 @@
-#
-# Copyright 2019 The Abseil Authors.
-#
-# 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
-#
-#      https://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.
-#
-
-absl_cc_library(
-  NAME
-    bind_front
-  SRCS
-    "internal/front_binder.h"
-  HDRS
-    "bind_front.h"
-  COPTS
-    ${ABSL_DEFAULT_COPTS}
-  DEPS
-    absl::base_internal
-    absl::compressed_tuple
-  PUBLIC
-)
-
-absl_cc_test(
-  NAME
-    bind_front_test
-  SRCS
-    "bind_front_test.cc"
-  COPTS
-    ${ABSL_DEFAULT_COPTS}
-  DEPS
-    absl::bind_front
-    absl::memory
-    gmock_main
-)
-
-absl_cc_library(
-  NAME
-    function_ref
-  SRCS
-    "internal/function_ref.h"
-  HDRS
-    "function_ref.h"
-  COPTS
-    ${ABSL_DEFAULT_COPTS}
-  DEPS
-    absl::base_internal
-    absl::meta
-  PUBLIC
-)
-
-absl_cc_test(
-  NAME
-    function_ref_test
-  SRCS
-    "function_ref_test.cc"
-  COPTS
-    ${ABSL_TEST_COPTS}
-  DEPS
-    absl::function_ref
-    absl::memory
-    absl::test_instance_tracker
-    gmock_main
-)
diff --git a/third_party/abseil_cpp/absl/functional/bind_front.h b/third_party/abseil_cpp/absl/functional/bind_front.h
deleted file mode 100644
index 5b47970e3577..000000000000
--- a/third_party/abseil_cpp/absl/functional/bind_front.h
+++ /dev/null
@@ -1,184 +0,0 @@
-// Copyright 2018 The Abseil Authors.
-//
-// 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
-//
-//      https://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.
-//
-// -----------------------------------------------------------------------------
-// File: bind_front.h
-// -----------------------------------------------------------------------------
-//
-// `absl::bind_front()` returns a functor by binding a number of arguments to
-// the front of a provided (usually more generic) functor. Unlike `std::bind`,
-// it does not require the use of argument placeholders. The simpler syntax of
-// `absl::bind_front()` allows you to avoid known misuses with `std::bind()`.
-//
-// `absl::bind_front()` is meant as a drop-in replacement for C++20's upcoming
-// `std::bind_front()`, which similarly resolves these issues with
-// `std::bind()`. Both `bind_front()` alternatives, unlike `std::bind()`, allow
-// partial function application. (See
-// https://en.wikipedia.org/wiki/Partial_application).
-
-#ifndef ABSL_FUNCTIONAL_BIND_FRONT_H_
-#define ABSL_FUNCTIONAL_BIND_FRONT_H_
-
-#include "absl/functional/internal/front_binder.h"
-#include "absl/utility/utility.h"
-
-namespace absl {
-ABSL_NAMESPACE_BEGIN
-
-// bind_front()
-//
-// Binds the first N arguments of an invocable object and stores them by value.
-//
-// Like `std::bind()`, `absl::bind_front()` is implicitly convertible to
-// `std::function`.  In particular, it may be used as a simpler replacement for
-// `std::bind()` in most cases, as it does not require  placeholders to be
-// specified. More importantly, it provides more reliable correctness guarantees
-// than `std::bind()`; while `std::bind()` will silently ignore passing more
-// parameters than expected, for example, `absl::bind_front()` will report such
-// mis-uses as errors.
-//
-// absl::bind_front(a...) can be seen as storing the results of
-// std::make_tuple(a...).
-//
-// Example: Binding a free function.
-//
-//   int Minus(int a, int b) { return a - b; }
-//
-//   assert(absl::bind_front(Minus)(3, 2) == 3 - 2);
-//   assert(absl::bind_front(Minus, 3)(2) == 3 - 2);
-//   assert(absl::bind_front(Minus, 3, 2)() == 3 - 2);
-//
-// Example: Binding a member function.
-//
-//   struct Math {
-//     int Double(int a) const { return 2 * a; }
-//   };
-//
-//   Math math;
-//
-//   assert(absl::bind_front(&Math::Double)(&math, 3) == 2 * 3);
-//   // Stores a pointer to math inside the functor.
-//   assert(absl::bind_front(&Math::Double, &math)(3) == 2 * 3);
-//   // Stores a copy of math inside the functor.
-//   assert(absl::bind_front(&Math::Double, math)(3) == 2 * 3);
-//   // Stores std::unique_ptr<Math> inside the functor.
-//   assert(absl::bind_front(&Math::Double,
-//                           std::unique_ptr<Math>(new Math))(3) == 2 * 3);
-//
-// Example: Using `absl::bind_front()`, instead of `std::bind()`, with
-//          `std::function`.
-//
-//   class FileReader {
-//    public:
-//     void ReadFileAsync(const std::string& filename, std::string* content,
-//                        const std::function<void()>& done) {
-//       // Calls Executor::Schedule(std::function<void()>).
-//       Executor::DefaultExecutor()->Schedule(
-//           absl::bind_front(&FileReader::BlockingRead, this,
-//                            filename, content, done));
-//     }
-//
-//    private:
-//     void BlockingRead(const std::string& filename, std::string* content,
-//                       const std::function<void()>& done) {
-//       CHECK_OK(file::GetContents(filename, content, {}));
-//       done();
-//     }
-//   };
-//
-// `absl::bind_front()` stores bound arguments explicitly using the type passed
-// rather than implicitly based on the type accepted by its functor.
-//
-// Example: Binding arguments explicitly.
-//
-//   void LogStringView(absl::string_view sv) {
-//     LOG(INFO) << sv;
-//   }
-//
-//   Executor* e = Executor::DefaultExecutor();
-//   std::string s = "hello";
-//   absl::string_view sv = s;
-//
-//   // absl::bind_front(LogStringView, arg) makes a copy of arg and stores it.
-//   e->Schedule(absl::bind_front(LogStringView, sv)); // ERROR: dangling
-//                                                     // string_view.
-//
-//   e->Schedule(absl::bind_front(LogStringView, s));  // OK: stores a copy of
-//                                                     // s.
-//
-// To store some of the arguments passed to `absl::bind_front()` by reference,
-//  use std::ref()` and `std::cref()`.
-//
-// Example: Storing some of the bound arguments by reference.
-//
-//   class Service {
-//    public:
-//     void Serve(const Request& req, std::function<void()>* done) {
-//       // The request protocol buffer won't be deleted until done is called.
-//       // It's safe to store a reference to it inside the functor.
-//       Executor::DefaultExecutor()->Schedule(
-//           absl::bind_front(&Service::BlockingServe, this, std::cref(req),
-//           done));
-//     }
-//
-//    private:
-//     void BlockingServe(const Request& req, std::function<void()>* done);
-//   };
-//
-// Example: Storing bound arguments by reference.
-//
-//   void Print(const std::string& a, const std::string& b) {
-//     std::cerr << a << b;
-//   }
-//
-//   std::string hi = "Hello, ";
-//   std::vector<std::string> names = {"Chuk", "Gek"};
-//   // Doesn't copy hi.
-//   for_each(names.begin(), names.end(),
-//            absl::bind_front(Print, std::ref(hi)));
-//
-//   // DO NOT DO THIS: the functor may outlive "hi", resulting in
-//   // dangling references.
-//   foo->DoInFuture(absl::bind_front(Print, std::ref(hi), "Guest"));  // BAD!
-//   auto f = absl::bind_front(Print, std::ref(hi), "Guest"); // BAD!
-//
-// Example: Storing reference-like types.
-//
-//   void Print(absl::string_view a, const std::string& b) {
-//     std::cerr << a << b;
-//   }
-//
-//   std::string hi = "Hello, ";
-//   // Copies "hi".
-//   absl::bind_front(Print, hi)("Chuk");
-//
-//   // Compile error: std::reference_wrapper<const string> is not implicitly
-//   // convertible to string_view.
-//   // absl::bind_front(Print, std::cref(hi))("Chuk");
-//
-//   // Doesn't copy "hi".
-//   absl::bind_front(Print, absl::string_view(hi))("Chuk");
-//
-template <class F, class... BoundArgs>
-constexpr functional_internal::bind_front_t<F, BoundArgs...> bind_front(
-    F&& func, BoundArgs&&... args) {
-  return functional_internal::bind_front_t<F, BoundArgs...>(
-      absl::in_place, absl::forward<F>(func),
-      absl::forward<BoundArgs>(args)...);
-}
-
-ABSL_NAMESPACE_END
-}  // namespace absl
-
-#endif  // ABSL_FUNCTIONAL_BIND_FRONT_H_
diff --git a/third_party/abseil_cpp/absl/functional/bind_front_test.cc b/third_party/abseil_cpp/absl/functional/bind_front_test.cc
deleted file mode 100644
index 4801a81caf0d..000000000000
--- a/third_party/abseil_cpp/absl/functional/bind_front_test.cc
+++ /dev/null
@@ -1,231 +0,0 @@
-// Copyright 2018 The Abseil Authors.
-//
-// 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
-//
-//      https://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.
-
-#include "absl/functional/bind_front.h"
-
-#include <stddef.h>
-
-#include <functional>
-#include <memory>
-#include <string>
-
-#include "gmock/gmock.h"
-#include "gtest/gtest.h"
-#include "absl/memory/memory.h"
-
-namespace {
-
-char CharAt(const char* s, size_t index) { return s[index]; }
-
-TEST(BindTest, Basics) {
-  EXPECT_EQ('C', absl::bind_front(CharAt)("ABC", 2));
-  EXPECT_EQ('C', absl::bind_front(CharAt, "ABC")(2));
-  EXPECT_EQ('C', absl::bind_front(CharAt, "ABC", 2)());
-}
-
-TEST(BindTest, Lambda) {
-  auto lambda = [](int x, int y, int z) { return x + y + z; };
-  EXPECT_EQ(6, absl::bind_front(lambda)(1, 2, 3));
-  EXPECT_EQ(6, absl::bind_front(lambda, 1)(2, 3));
-  EXPECT_EQ(6, absl::bind_front(lambda, 1, 2)(3));
-  EXPECT_EQ(6, absl::bind_front(lambda, 1, 2, 3)());
-}
-
-struct Functor {
-  std::string operator()() & { return "&"; }
-  std::string operator()() const& { return "const&"; }
-  std::string operator()() && { return "&&"; }
-  std::string operator()() const&& { return "const&&"; }
-};
-
-TEST(BindTest, PerfectForwardingOfBoundArgs) {
-  auto f = absl::bind_front(Functor());
-  const auto& cf = f;
-  EXPECT_EQ("&", f());
-  EXPECT_EQ("const&", cf());
-  EXPECT_EQ("&&", std::move(f)());
-  EXPECT_EQ("const&&", std::move(cf)());
-}
-
-struct ArgDescribe {
-  std::string operator()(int&) const { return "&"; }             // NOLINT
-  std::string operator()(const int&) const { return "const&"; }  // NOLINT
-  std::string operator()(int&&) const { return "&&"; }
-  std::string operator()(const int&&) const { return "const&&"; }
-};
-
-TEST(BindTest, PerfectForwardingOfFreeArgs) {
-  ArgDescribe f;
-  int i;
-  EXPECT_EQ("&", absl::bind_front(f)(static_cast<int&>(i)));
-  EXPECT_EQ("const&", absl::bind_front(f)(static_cast<const int&>(i)));
-  EXPECT_EQ("&&", absl::bind_front(f)(static_cast<int&&>(i)));
-  EXPECT_EQ("const&&", absl::bind_front(f)(static_cast<const int&&>(i)));
-}
-
-struct NonCopyableFunctor {
-  NonCopyableFunctor() = default;
-  NonCopyableFunctor(const NonCopyableFunctor&) = delete;
-  NonCopyableFunctor& operator=(const NonCopyableFunctor&) = delete;
-  const NonCopyableFunctor* operator()() const { return this; }
-};
-
-TEST(BindTest, RefToFunctor) {
-  // It won't copy/move the functor and use the original object.
-  NonCopyableFunctor ncf;
-  auto bound_ncf = absl::bind_front(std::ref(ncf));
-  auto bound_ncf_copy = bound_ncf;
-  EXPECT_EQ(&ncf, bound_ncf_copy());
-}
-
-struct Struct {
-  std::string value;
-};
-
-TEST(BindTest, StoreByCopy) {
-  Struct s = {"hello"};
-  auto f = absl::bind_front(&Struct::value, s);
-  auto g = f;
-  EXPECT_EQ("hello", f());
-  EXPECT_EQ("hello", g());
-  EXPECT_NE(&s.value, &f());
-  EXPECT_NE(&s.value, &g());
-  EXPECT_NE(&g(), &f());
-}
-
-struct NonCopyable {
-  explicit NonCopyable(const std::string& s) : value(s) {}
-  NonCopyable(const NonCopyable&) = delete;
-  NonCopyable& operator=(const NonCopyable&) = delete;
-
-  std::string value;
-};
-
-const std::string& GetNonCopyableValue(const NonCopyable& n) { return n.value; }
-
-TEST(BindTest, StoreByRef) {
-  NonCopyable s("hello");
-  auto f = absl::bind_front(&GetNonCopyableValue, std::ref(s));
-  EXPECT_EQ("hello", f());
-  EXPECT_EQ(&s.value, &f());
-  auto g = std::move(f);  // NOLINT
-  EXPECT_EQ("hello", g());
-  EXPECT_EQ(&s.value, &g());
-  s.value = "goodbye";
-  EXPECT_EQ("goodbye", g());
-}
-
-TEST(BindTest, StoreByCRef) {
-  NonCopyable s("hello");
-  auto f = absl::bind_front(&GetNonCopyableValue, std::cref(s));
-  EXPECT_EQ("hello", f());
-  EXPECT_EQ(&s.value, &f());
-  auto g = std::move(f);  // NOLINT
-  EXPECT_EQ("hello", g());
-  EXPECT_EQ(&s.value, &g());
-  s.value = "goodbye";
-  EXPECT_EQ("goodbye", g());
-}
-
-const std::string& GetNonCopyableValueByWrapper(
-    std::reference_wrapper<NonCopyable> n) {
-  return n.get().value;
-}
-
-TEST(BindTest, StoreByRefInvokeByWrapper) {
-  NonCopyable s("hello");
-  auto f = absl::bind_front(GetNonCopyableValueByWrapper, std::ref(s));
-  EXPECT_EQ("hello", f());
-  EXPECT_EQ(&s.value, &f());
-  auto g = std::move(f);
-  EXPECT_EQ("hello", g());
-  EXPECT_EQ(&s.value, &g());
-  s.value = "goodbye";
-  EXPECT_EQ("goodbye", g());
-}
-
-TEST(BindTest, StoreByPointer) {
-  NonCopyable s("hello");
-  auto f = absl::bind_front(&NonCopyable::value, &s);
-  EXPECT_EQ("hello", f());
-  EXPECT_EQ(&s.value, &f());
-  auto g = std::move(f);
-  EXPECT_EQ("hello", g());
-  EXPECT_EQ(&s.value, &g());
-}
-
-int Sink(std::unique_ptr<int> p) {
-  return *p;
-}
-
-std::unique_ptr<int> Factory(int n) { return absl::make_unique<int>(n); }
-
-TEST(BindTest, NonCopyableArg) {
-  EXPECT_EQ(42, absl::bind_front(Sink)(absl::make_unique<int>(42)));
-  EXPECT_EQ(42, absl::bind_front(Sink, absl::make_unique<int>(42))());
-}
-
-TEST(BindTest, NonCopyableResult) {
-  EXPECT_THAT(absl::bind_front(Factory)(42), ::testing::Pointee(42));
-  EXPECT_THAT(absl::bind_front(Factory, 42)(), ::testing::Pointee(42));
-}
-
-// is_copy_constructible<FalseCopyable<unique_ptr<T>> is true but an attempt to
-// instantiate the copy constructor leads to a compile error. This is similar
-// to how standard containers behave.
-template <class T>
-struct FalseCopyable {
-  FalseCopyable() {}
-  FalseCopyable(const FalseCopyable& other) : m(other.m) {}
-  FalseCopyable(FalseCopyable&& other) : m(std::move(other.m)) {}
-  T m;
-};
-
-int GetMember(FalseCopyable<std::unique_ptr<int>> x) { return *x.m; }
-
-TEST(BindTest, WrappedMoveOnly) {
-  FalseCopyable<std::unique_ptr<int>> x;
-  x.m = absl::make_unique<int>(42);
-  auto f = absl::bind_front(&GetMember, std::move(x));
-  EXPECT_EQ(42, std::move(f)());
-}
-
-int Plus(int a, int b) { return a + b; }
-
-TEST(BindTest, ConstExpr) {
-  constexpr auto f = absl::bind_front(CharAt);
-  EXPECT_EQ(f("ABC", 1), 'B');
-  static constexpr int five = 5;
-  constexpr auto plus5 = absl::bind_front(Plus, five);
-  EXPECT_EQ(plus5(1), 6);
-
-  // There seems to be a bug in MSVC dealing constexpr construction of
-  // char[]. Notice 'plus5' above; 'int' works just fine.
-#if !(defined(_MSC_VER) && _MSC_VER < 1910)
-  static constexpr char data[] = "DEF";
-  constexpr auto g = absl::bind_front(CharAt, data);
-  EXPECT_EQ(g(1), 'E');
-#endif
-}
-
-struct ManglingCall {
-  int operator()(int, double, std::string) const { return 0; }
-};
-
-TEST(BindTest, Mangling) {
-  // We just want to generate a particular instantiation to see its mangling.
-  absl::bind_front(ManglingCall{}, 1, 3.3)("A");
-}
-
-}  // namespace
diff --git a/third_party/abseil_cpp/absl/functional/function_ref.h b/third_party/abseil_cpp/absl/functional/function_ref.h
deleted file mode 100644
index 6e03ac2e04e9..000000000000
--- a/third_party/abseil_cpp/absl/functional/function_ref.h
+++ /dev/null
@@ -1,139 +0,0 @@
-// Copyright 2019 The Abseil Authors.
-//
-// 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
-//
-//      https://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.
-//
-// -----------------------------------------------------------------------------
-// File: function_ref.h
-// -----------------------------------------------------------------------------
-//
-// This header file defines the `absl::FunctionRef` type for holding a
-// non-owning reference to an object of any invocable type. This function
-// reference is typically most useful as a type-erased argument type for
-// accepting function types that neither take ownership nor copy the type; using
-// the reference type in this case avoids a copy and an allocation. Best
-// practices of other non-owning reference-like objects (such as
-// `absl::string_view`) apply here.
-//
-//  An `absl::FunctionRef` is similar in usage to a `std::function` but has the
-//  following differences:
-//
-//  * It doesn't own the underlying object.
-//  * It doesn't have a null or empty state.
-//  * It never performs deep copies or allocations.
-//  * It's much faster and cheaper to construct.
-//  * It's trivially copyable and destructable.
-//
-// Generally, `absl::FunctionRef` should not be used as a return value, data
-// member, or to initialize a `std::function`. Such usages will often lead to
-// problematic lifetime issues. Once you convert something to an
-// `absl::FunctionRef` you cannot make a deep copy later.
-//
-// This class is suitable for use wherever a "const std::function<>&"
-// would be used without making a copy. ForEach functions and other versions of
-// the visitor pattern are a good example of when this class should be used.
-//
-// This class is trivial to copy and should be passed by value.
-#ifndef ABSL_FUNCTIONAL_FUNCTION_REF_H_
-#define ABSL_FUNCTIONAL_FUNCTION_REF_H_
-
-#include <cassert>
-#include <functional>
-#include <type_traits>
-
-#include "absl/functional/internal/function_ref.h"
-#include "absl/meta/type_traits.h"
-
-namespace absl {
-ABSL_NAMESPACE_BEGIN
-
-// FunctionRef
-//
-// Dummy class declaration to allow the partial specialization based on function
-// types below.
-template <typename T>
-class FunctionRef;
-
-// FunctionRef
-//
-// An `absl::FunctionRef` is a lightweight wrapper to any invokable object with
-// a compatible signature. Generally, an `absl::FunctionRef` should only be used
-// as an argument type and should be preferred as an argument over a const
-// reference to a `std::function`.
-//
-// Example:
-//
-//   // The following function takes a function callback by const reference
-//   bool Visitor(const std::function<void(my_proto&,
-//                                         absl::string_view)>& callback);
-//
-//   // Assuming that the function is not stored or otherwise copied, it can be
-//   // replaced by an `absl::FunctionRef`:
-//   bool Visitor(absl::FunctionRef<void(my_proto&, absl::string_view)>
-//                  callback);
-//
-// Note: the assignment operator within an `absl::FunctionRef` is intentionally
-// deleted to prevent misuse; because the `absl::FunctionRef` does not own the
-// underlying type, assignment likely indicates misuse.
-template <typename R, typename... Args>
-class FunctionRef<R(Args...)> {
- private:
-  // Used to disable constructors for objects that are not compatible with the
-  // signature of this FunctionRef.
-  template <typename F,
-            typename FR = absl::base_internal::invoke_result_t<F, Args&&...>>
-  using EnableIfCompatible =
-      typename std::enable_if<std::is_void<R>::value ||
-                              std::is_convertible<FR, R>::value>::type;
-
- public:
-  // Constructs a FunctionRef from any invokable type.
-  template <typename F, typename = EnableIfCompatible<const F&>>
-  FunctionRef(const F& f)  // NOLINT(runtime/explicit)
-      : invoker_(&absl::functional_internal::InvokeObject<F, R, Args...>) {
-    absl::functional_internal::AssertNonNull(f);
-    ptr_.obj = &f;
-  }
-
-  // Overload for function pointers. This eliminates a level of indirection that
-  // would happen if the above overload was used (it lets us store the pointer
-  // instead of a pointer to a pointer).
-  //
-  // This overload is also used for references to functions, since references to
-  // functions can decay to function pointers implicitly.
-  template <
-      typename F, typename = EnableIfCompatible<F*>,
-      absl::functional_internal::EnableIf<absl::is_function<F>::value> = 0>
-  FunctionRef(F* f)  // NOLINT(runtime/explicit)
-      : invoker_(&absl::functional_internal::InvokeFunction<F*, R, Args...>) {
-    assert(f != nullptr);
-    ptr_.fun = reinterpret_cast<decltype(ptr_.fun)>(f);
-  }
-
-  // To help prevent subtle lifetime bugs, FunctionRef is not assignable.
-  // Typically, it should only be used as an argument type.
-  FunctionRef& operator=(const FunctionRef& rhs) = delete;
-
-  // Call the underlying object.
-  R operator()(Args... args) const {
-    return invoker_(ptr_, std::forward<Args>(args)...);
-  }
-
- private:
-  absl::functional_internal::VoidPtr ptr_;
-  absl::functional_internal::Invoker<R, Args...> invoker_;
-};
-
-ABSL_NAMESPACE_END
-}  // namespace absl
-
-#endif  // ABSL_FUNCTIONAL_FUNCTION_REF_H_
diff --git a/third_party/abseil_cpp/absl/functional/function_ref_benchmark.cc b/third_party/abseil_cpp/absl/functional/function_ref_benchmark.cc
deleted file mode 100644
index 045305bfef30..000000000000
--- a/third_party/abseil_cpp/absl/functional/function_ref_benchmark.cc
+++ /dev/null
@@ -1,142 +0,0 @@
-// Copyright 2019 The Abseil Authors.
-//
-// 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
-//
-//      https://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.
-
-#include "absl/functional/function_ref.h"
-
-#include <memory>
-
-#include "benchmark/benchmark.h"
-#include "absl/base/attributes.h"
-
-namespace absl {
-ABSL_NAMESPACE_BEGIN
-namespace {
-
-int dummy = 0;
-
-void FreeFunction() { benchmark::DoNotOptimize(dummy); }
-
-struct TrivialFunctor {
-  void operator()() const { benchmark::DoNotOptimize(dummy); }
-};
-
-struct LargeFunctor {
-  void operator()() const { benchmark::DoNotOptimize(this); }
-  std::string a, b, c;
-};
-
-template <typename Function, typename... Args>
-void ABSL_ATTRIBUTE_NOINLINE CallFunction(Function f, Args&&... args) {
-  f(std::forward<Args>(args)...);
-}
-
-template <typename Function, typename Callable, typename... Args>
-void ConstructAndCallFunctionBenchmark(benchmark::State& state,
-                                       const Callable& c, Args&&... args) {
-  for (auto _ : state) {
-    CallFunction<Function>(c, std::forward<Args>(args)...);
-  }
-}
-
-void BM_TrivialStdFunction(benchmark::State& state) {
-  ConstructAndCallFunctionBenchmark<std::function<void()>>(state,
-                                                           TrivialFunctor{});
-}
-BENCHMARK(BM_TrivialStdFunction);
-
-void BM_TrivialFunctionRef(benchmark::State& state) {
-  ConstructAndCallFunctionBenchmark<FunctionRef<void()>>(state,
-                                                         TrivialFunctor{});
-}
-BENCHMARK(BM_TrivialFunctionRef);
-
-void BM_LargeStdFunction(benchmark::State& state) {
-  ConstructAndCallFunctionBenchmark<std::function<void()>>(state,
-                                                           LargeFunctor{});
-}
-BENCHMARK(BM_LargeStdFunction);
-
-void BM_LargeFunctionRef(benchmark::State& state) {
-  ConstructAndCallFunctionBenchmark<FunctionRef<void()>>(state, LargeFunctor{});
-}
-BENCHMARK(BM_LargeFunctionRef);
-
-void BM_FunPtrStdFunction(benchmark::State& state) {
-  ConstructAndCallFunctionBenchmark<std::function<void()>>(state, FreeFunction);
-}
-BENCHMARK(BM_FunPtrStdFunction);
-
-void BM_FunPtrFunctionRef(benchmark::State& state) {
-  ConstructAndCallFunctionBenchmark<FunctionRef<void()>>(state, FreeFunction);
-}
-BENCHMARK(BM_FunPtrFunctionRef);
-
-// Doesn't include construction or copy overhead in the loop.
-template <typename Function, typename Callable, typename... Args>
-void CallFunctionBenchmark(benchmark::State& state, const Callable& c,
-                           Args... args) {
-  Function f = c;
-  for (auto _ : state) {
-    benchmark::DoNotOptimize(&f);
-    f(args...);
-  }
-}
-
-struct FunctorWithTrivialArgs {
-  void operator()(int a, int b, int c) const {
-    benchmark::DoNotOptimize(a);
-    benchmark::DoNotOptimize(b);
-    benchmark::DoNotOptimize(c);
-  }
-};
-
-void BM_TrivialArgsStdFunction(benchmark::State& state) {
-  CallFunctionBenchmark<std::function<void(int, int, int)>>(
-      state, FunctorWithTrivialArgs{}, 1, 2, 3);
-}
-BENCHMARK(BM_TrivialArgsStdFunction);
-
-void BM_TrivialArgsFunctionRef(benchmark::State& state) {
-  CallFunctionBenchmark<FunctionRef<void(int, int, int)>>(
-      state, FunctorWithTrivialArgs{}, 1, 2, 3);
-}
-BENCHMARK(BM_TrivialArgsFunctionRef);
-
-struct FunctorWithNonTrivialArgs {
-  void operator()(std::string a, std::string b, std::string c) const {
-    benchmark::DoNotOptimize(&a);
-    benchmark::DoNotOptimize(&b);
-    benchmark::DoNotOptimize(&c);
-  }
-};
-
-void BM_NonTrivialArgsStdFunction(benchmark::State& state) {
-  std::string a, b, c;
-  CallFunctionBenchmark<
-      std::function<void(std::string, std::string, std::string)>>(
-      state, FunctorWithNonTrivialArgs{}, a, b, c);
-}
-BENCHMARK(BM_NonTrivialArgsStdFunction);
-
-void BM_NonTrivialArgsFunctionRef(benchmark::State& state) {
-  std::string a, b, c;
-  CallFunctionBenchmark<
-      FunctionRef<void(std::string, std::string, std::string)>>(
-      state, FunctorWithNonTrivialArgs{}, a, b, c);
-}
-BENCHMARK(BM_NonTrivialArgsFunctionRef);
-
-}  // namespace
-ABSL_NAMESPACE_END
-}  // namespace absl
diff --git a/third_party/abseil_cpp/absl/functional/function_ref_test.cc b/third_party/abseil_cpp/absl/functional/function_ref_test.cc
deleted file mode 100644
index 3aa59745873d..000000000000
--- a/third_party/abseil_cpp/absl/functional/function_ref_test.cc
+++ /dev/null
@@ -1,257 +0,0 @@
-// Copyright 2019 The Abseil Authors.
-//
-// 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
-//
-//      https://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.
-
-#include "absl/functional/function_ref.h"
-
-#include <memory>
-
-#include "gmock/gmock.h"
-#include "gtest/gtest.h"
-#include "absl/container/internal/test_instance_tracker.h"
-#include "absl/memory/memory.h"
-
-namespace absl {
-ABSL_NAMESPACE_BEGIN
-namespace {
-
-void RunFun(FunctionRef<void()> f) { f(); }
-
-TEST(FunctionRefTest, Lambda) {
-  bool ran = false;
-  RunFun([&] { ran = true; });
-  EXPECT_TRUE(ran);
-}
-
-int Function() { return 1337; }
-
-TEST(FunctionRefTest, Function1) {
-  FunctionRef<int()> ref(&Function);
-  EXPECT_EQ(1337, ref());
-}
-
-TEST(FunctionRefTest, Function2) {
-  FunctionRef<int()> ref(Function);
-  EXPECT_EQ(1337, ref());
-}
-
-int NoExceptFunction() noexcept { return 1337; }
-
-// TODO(jdennett): Add a test for noexcept member functions.
-TEST(FunctionRefTest, NoExceptFunction) {
-  FunctionRef<int()> ref(NoExceptFunction);
-  EXPECT_EQ(1337, ref());
-}
-
-TEST(FunctionRefTest, ForwardsArgs) {
-  auto l = [](std::unique_ptr<int> i) { return *i; };
-  FunctionRef<int(std::unique_ptr<int>)> ref(l);
-  EXPECT_EQ(42, ref(absl::make_unique<int>(42)));
-}
-
-TEST(FunctionRef, ReturnMoveOnly) {
-  auto l = [] { return absl::make_unique<int>(29); };
-  FunctionRef<std::unique_ptr<int>()> ref(l);
-  EXPECT_EQ(29, *ref());
-}
-
-TEST(FunctionRef, ManyArgs) {
-  auto l = [](int a, int b, int c) { return a + b + c; };
-  FunctionRef<int(int, int, int)> ref(l);
-  EXPECT_EQ(6, ref(1, 2, 3));
-}
-
-TEST(FunctionRef, VoidResultFromNonVoidFunctor) {
-  bool ran = false;
-  auto l = [&]() -> int {
-    ran = true;
-    return 2;
-  };
-  FunctionRef<void()> ref(l);
-  ref();
-  EXPECT_TRUE(ran);
-}
-
-TEST(FunctionRef, CastFromDerived) {
-  struct Base {};
-  struct Derived : public Base {};
-
-  Derived d;
-  auto l1 = [&](Base* b) { EXPECT_EQ(&d, b); };
-  FunctionRef<void(Derived*)> ref1(l1);
-  ref1(&d);
-
-  auto l2 = [&]() -> Derived* { return &d; };
-  FunctionRef<Base*()> ref2(l2);
-  EXPECT_EQ(&d, ref2());
-}
-
-TEST(FunctionRef, VoidResultFromNonVoidFuncton) {
-  FunctionRef<void()> ref(Function);
-  ref();
-}
-
-TEST(FunctionRef, MemberPtr) {
-  struct S {
-    int i;
-  };
-
-  S s{1100111};
-  auto mem_ptr = &S::i;
-  FunctionRef<int(const S& s)> ref(mem_ptr);
-  EXPECT_EQ(1100111, ref(s));
-}
-
-TEST(FunctionRef, MemberFun) {
-  struct S {
-    int i;
-    int get_i() const { return i; }
-  };
-
-  S s{22};
-  auto mem_fun_ptr = &S::get_i;
-  FunctionRef<int(const S& s)> ref(mem_fun_ptr);
-  EXPECT_EQ(22, ref(s));
-}
-
-TEST(FunctionRef, MemberFunRefqualified) {
-  struct S {
-    int i;
-    int get_i() && { return i; }
-  };
-  auto mem_fun_ptr = &S::get_i;
-  S s{22};
-  FunctionRef<int(S && s)> ref(mem_fun_ptr);
-  EXPECT_EQ(22, ref(std::move(s)));
-}
-
-#if !defined(_WIN32) && defined(GTEST_HAS_DEATH_TEST)
-
-TEST(FunctionRef, MemberFunRefqualifiedNull) {
-  struct S {
-    int i;
-    int get_i() && { return i; }
-  };
-  auto mem_fun_ptr = &S::get_i;
-  mem_fun_ptr = nullptr;
-  EXPECT_DEBUG_DEATH({ FunctionRef<int(S && s)> ref(mem_fun_ptr); }, "");
-}
-
-TEST(FunctionRef, NullMemberPtrAssertFails) {
-  struct S {
-    int i;
-  };
-  using MemberPtr = int S::*;
-  MemberPtr mem_ptr = nullptr;
-  EXPECT_DEBUG_DEATH({ FunctionRef<int(const S& s)> ref(mem_ptr); }, "");
-}
-
-#endif  // GTEST_HAS_DEATH_TEST
-
-TEST(FunctionRef, CopiesAndMovesPerPassByValue) {
-  absl::test_internal::InstanceTracker tracker;
-  absl::test_internal::CopyableMovableInstance instance(0);
-  auto l = [](absl::test_internal::CopyableMovableInstance) {};
-  FunctionRef<void(absl::test_internal::CopyableMovableInstance)> ref(l);
-  ref(instance);
-  EXPECT_EQ(tracker.copies(), 1);
-  EXPECT_EQ(tracker.moves(), 1);
-}
-
-TEST(FunctionRef, CopiesAndMovesPerPassByRef) {
-  absl::test_internal::InstanceTracker tracker;
-  absl::test_internal::CopyableMovableInstance instance(0);
-  auto l = [](const absl::test_internal::CopyableMovableInstance&) {};
-  FunctionRef<void(const absl::test_internal::CopyableMovableInstance&)> ref(l);
-  ref(instance);
-  EXPECT_EQ(tracker.copies(), 0);
-  EXPECT_EQ(tracker.moves(), 0);
-}
-
-TEST(FunctionRef, CopiesAndMovesPerPassByValueCallByMove) {
-  absl::test_internal::InstanceTracker tracker;
-  absl::test_internal::CopyableMovableInstance instance(0);
-  auto l = [](absl::test_internal::CopyableMovableInstance) {};
-  FunctionRef<void(absl::test_internal::CopyableMovableInstance)> ref(l);
-  ref(std::move(instance));
-  EXPECT_EQ(tracker.copies(), 0);
-  EXPECT_EQ(tracker.moves(), 2);
-}
-
-TEST(FunctionRef, CopiesAndMovesPerPassByValueToRef) {
-  absl::test_internal::InstanceTracker tracker;
-  absl::test_internal::CopyableMovableInstance instance(0);
-  auto l = [](const absl::test_internal::CopyableMovableInstance&) {};
-  FunctionRef<void(absl::test_internal::CopyableMovableInstance)> ref(l);
-  ref(std::move(instance));
-  EXPECT_EQ(tracker.copies(), 0);
-  EXPECT_EQ(tracker.moves(), 1);
-}
-
-TEST(FunctionRef, PassByValueTypes) {
-  using absl::functional_internal::Invoker;
-  using absl::functional_internal::VoidPtr;
-  using absl::test_internal::CopyableMovableInstance;
-  struct Trivial {
-    void* p[2];
-  };
-  struct LargeTrivial {
-    void* p[3];
-  };
-
-  static_assert(std::is_same<Invoker<void, int>, void (*)(VoidPtr, int)>::value,
-                "Scalar types should be passed by value");
-  static_assert(
-      std::is_same<Invoker<void, Trivial>, void (*)(VoidPtr, Trivial)>::value,
-      "Small trivial types should be passed by value");
-  static_assert(std::is_same<Invoker<void, LargeTrivial>,
-                             void (*)(VoidPtr, LargeTrivial &&)>::value,
-                "Large trivial types should be passed by rvalue reference");
-  static_assert(
-      std::is_same<Invoker<void, CopyableMovableInstance>,
-                   void (*)(VoidPtr, CopyableMovableInstance &&)>::value,
-      "Types with copy/move ctor should be passed by rvalue reference");
-
-  // References are passed as references.
-  static_assert(
-      std::is_same<Invoker<void, int&>, void (*)(VoidPtr, int&)>::value,
-      "Reference types should be preserved");
-  static_assert(
-      std::is_same<Invoker<void, CopyableMovableInstance&>,
-                   void (*)(VoidPtr, CopyableMovableInstance&)>::value,
-      "Reference types should be preserved");
-  static_assert(
-      std::is_same<Invoker<void, CopyableMovableInstance&&>,
-                   void (*)(VoidPtr, CopyableMovableInstance &&)>::value,
-      "Reference types should be preserved");
-
-  // Make sure the address of an object received by reference is the same as the
-  // addess of the object passed by the caller.
-  {
-    LargeTrivial obj;
-    auto test = [&obj](LargeTrivial& input) { ASSERT_EQ(&input, &obj); };
-    absl::FunctionRef<void(LargeTrivial&)> ref(test);
-    ref(obj);
-  }
-
-  {
-    Trivial obj;
-    auto test = [&obj](Trivial& input) { ASSERT_EQ(&input, &obj); };
-    absl::FunctionRef<void(Trivial&)> ref(test);
-    ref(obj);
-  }
-}
-
-}  // namespace
-ABSL_NAMESPACE_END
-}  // namespace absl
diff --git a/third_party/abseil_cpp/absl/functional/internal/front_binder.h b/third_party/abseil_cpp/absl/functional/internal/front_binder.h
deleted file mode 100644
index 45f52de73d25..000000000000
--- a/third_party/abseil_cpp/absl/functional/internal/front_binder.h
+++ /dev/null
@@ -1,95 +0,0 @@
-// Copyright 2018 The Abseil Authors.
-//
-// 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
-//
-//      https://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.
-
-// Implementation details for `absl::bind_front()`.
-
-#ifndef ABSL_FUNCTIONAL_INTERNAL_FRONT_BINDER_H_
-#define ABSL_FUNCTIONAL_INTERNAL_FRONT_BINDER_H_
-
-#include <cstddef>
-#include <type_traits>
-#include <utility>
-
-#include "absl/base/internal/invoke.h"
-#include "absl/container/internal/compressed_tuple.h"
-#include "absl/meta/type_traits.h"
-#include "absl/utility/utility.h"
-
-namespace absl {
-ABSL_NAMESPACE_BEGIN
-namespace functional_internal {
-
-// Invoke the method, expanding the tuple of bound arguments.
-template <class R, class Tuple, size_t... Idx, class... Args>
-R Apply(Tuple&& bound, absl::index_sequence<Idx...>, Args&&... free) {
-  return base_internal::invoke(
-      absl::forward<Tuple>(bound).template get<Idx>()...,
-      absl::forward<Args>(free)...);
-}
-
-template <class F, class... BoundArgs>
-class FrontBinder {
-  using BoundArgsT = absl::container_internal::CompressedTuple<F, BoundArgs...>;
-  using Idx = absl::make_index_sequence<sizeof...(BoundArgs) + 1>;
-
-  BoundArgsT bound_args_;
-
- public:
-  template <class... Ts>
-  constexpr explicit FrontBinder(absl::in_place_t, Ts&&... ts)
-      : bound_args_(absl::forward<Ts>(ts)...) {}
-
-  template <class... FreeArgs, class R = base_internal::invoke_result_t<
-                                   F&, BoundArgs&..., FreeArgs&&...>>
-  R operator()(FreeArgs&&... free_args) & {
-    return functional_internal::Apply<R>(bound_args_, Idx(),
-                                         absl::forward<FreeArgs>(free_args)...);
-  }
-
-  template <class... FreeArgs,
-            class R = base_internal::invoke_result_t<
-                const F&, const BoundArgs&..., FreeArgs&&...>>
-  R operator()(FreeArgs&&... free_args) const& {
-    return functional_internal::Apply<R>(bound_args_, Idx(),
-                                         absl::forward<FreeArgs>(free_args)...);
-  }
-
-  template <class... FreeArgs, class R = base_internal::invoke_result_t<
-                                   F&&, BoundArgs&&..., FreeArgs&&...>>
-  R operator()(FreeArgs&&... free_args) && {
-    // This overload is called when *this is an rvalue. If some of the bound
-    // arguments are stored by value or rvalue reference, we move them.
-    return functional_internal::Apply<R>(absl::move(bound_args_), Idx(),
-                                         absl::forward<FreeArgs>(free_args)...);
-  }
-
-  template <class... FreeArgs,
-            class R = base_internal::invoke_result_t<
-                const F&&, const BoundArgs&&..., FreeArgs&&...>>
-  R operator()(FreeArgs&&... free_args) const&& {
-    // This overload is called when *this is an rvalue. If some of the bound
-    // arguments are stored by value or rvalue reference, we move them.
-    return functional_internal::Apply<R>(absl::move(bound_args_), Idx(),
-                                         absl::forward<FreeArgs>(free_args)...);
-  }
-};
-
-template <class F, class... BoundArgs>
-using bind_front_t = FrontBinder<decay_t<F>, absl::decay_t<BoundArgs>...>;
-
-}  // namespace functional_internal
-ABSL_NAMESPACE_END
-}  // namespace absl
-
-#endif  // ABSL_FUNCTIONAL_INTERNAL_FRONT_BINDER_H_
diff --git a/third_party/abseil_cpp/absl/functional/internal/function_ref.h b/third_party/abseil_cpp/absl/functional/internal/function_ref.h
deleted file mode 100644
index b5bb8b430a81..000000000000
--- a/third_party/abseil_cpp/absl/functional/internal/function_ref.h
+++ /dev/null
@@ -1,106 +0,0 @@
-// Copyright 2019 The Abseil Authors.
-//
-// 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
-//
-//      https://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.
-
-#ifndef ABSL_FUNCTIONAL_INTERNAL_FUNCTION_REF_H_
-#define ABSL_FUNCTIONAL_INTERNAL_FUNCTION_REF_H_
-
-#include <cassert>
-#include <functional>
-#include <type_traits>
-
-#include "absl/base/internal/invoke.h"
-#include "absl/meta/type_traits.h"
-
-namespace absl {
-ABSL_NAMESPACE_BEGIN
-namespace functional_internal {
-
-// Like a void* that can handle function pointers as well. The standard does not
-// allow function pointers to round-trip through void*, but void(*)() is fine.
-//
-// Note: It's important that this class remains trivial and is the same size as
-// a pointer, since this allows the compiler to perform tail-call optimizations
-// when the underlying function is a callable object with a matching signature.
-union VoidPtr {
-  const void* obj;
-  void (*fun)();
-};
-
-// Chooses the best type for passing T as an argument.
-// Attempt to be close to SystemV AMD64 ABI. Objects with trivial copy ctor are
-// passed by value.
-template <typename T>
-constexpr bool PassByValue() {
-  return !std::is_lvalue_reference<T>::value &&
-         absl::is_trivially_copy_constructible<T>::value &&
-         absl::is_trivially_copy_assignable<
-             typename std::remove_cv<T>::type>::value &&
-         std::is_trivially_destructible<T>::value &&
-         sizeof(T) <= 2 * sizeof(void*);
-}
-
-template <typename T>
-struct ForwardT : std::conditional<PassByValue<T>(), T, T&&> {};
-
-// An Invoker takes a pointer to the type-erased invokable object, followed by
-// the arguments that the invokable object expects.
-//
-// Note: The order of arguments here is an optimization, since member functions
-// have an implicit "this" pointer as their first argument, putting VoidPtr
-// first allows the compiler to perform tail-call optimization in many cases.
-template <typename R, typename... Args>
-using Invoker = R (*)(VoidPtr, typename ForwardT<Args>::type...);
-
-//
-// InvokeObject and InvokeFunction provide static "Invoke" functions that can be
-// used as Invokers for objects or functions respectively.
-//
-// static_cast<R> handles the case the return type is void.
-template <typename Obj, typename R, typename... Args>
-R InvokeObject(VoidPtr ptr, typename ForwardT<Args>::type... args) {
-  auto o = static_cast<const Obj*>(ptr.obj);
-  return static_cast<R>(
-      absl::base_internal::invoke(*o, std::forward<Args>(args)...));
-}
-
-template <typename Fun, typename R, typename... Args>
-R InvokeFunction(VoidPtr ptr, typename ForwardT<Args>::type... args) {
-  auto f = reinterpret_cast<Fun>(ptr.fun);
-  return static_cast<R>(
-      absl::base_internal::invoke(f, std::forward<Args>(args)...));
-}
-
-template <typename Sig>
-void AssertNonNull(const std::function<Sig>& f) {
-  assert(f != nullptr);
-  (void)f;
-}
-
-template <typename F>
-void AssertNonNull(const F&) {}
-
-template <typename F, typename C>
-void AssertNonNull(F C::*f) {
-  assert(f != nullptr);
-  (void)f;
-}
-
-template <bool C>
-using EnableIf = typename ::std::enable_if<C, int>::type;
-
-}  // namespace functional_internal
-ABSL_NAMESPACE_END
-}  // namespace absl
-
-#endif  // ABSL_FUNCTIONAL_INTERNAL_FUNCTION_REF_H_