Rewrite rtc::Bind using variadic templates.

webrtc/base/bind_unittest.cc

 /*
  *  Copyright 2004 The WebRTC Project Authors. All rights reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
+#include <type_traits>
+
 #include "webrtc/base/bind.h"
 #include "webrtc/base/gunit.h"
 
 #include "webrtc/base/refcount.h"
 
 namespace rtc {
 
 namespace {
 
 struct LifeTimeCheck;
@@ skipping 43 matching lines @@
 };
 
 int Return42() { return 42; }
 int Negate(int a) { return -a; }
 int Multiply(int a, int b) { return a * b; }
 
 }  // namespace
 
 // Try to catch any problem with scoped_refptr type deduction in rtc::Bind at
 // compile time.
-static_assert(
-    is_same<
-        rtc::remove_reference<const scoped_refptr<RefCountInterface>&>::type,
-        const scoped_refptr<RefCountInterface>>::value,
-    "const scoped_refptr& should be captured by value");
-
-static_assert(is_same<rtc::remove_reference<const scoped_refptr<F>&>::type,
-                      const scoped_refptr<F>>::value,
-              "const scoped_refptr& should be captured by value");
-
-static_assert(
-    is_same<rtc::remove_reference<const int&>::type, const int>::value,
-    "const int& should be captured as const int");
-
-static_assert(is_same<rtc::remove_reference<const F&>::type, const F>::value,
-              "const F& should be captured as const F");
-
-static_assert(is_same<rtc::remove_reference<F&>::type, F>::value,
-              "F& should be captured as F");
-
 #define EXPECT_IS_CAPTURED_AS_PTR(T)                              \
   static_assert(is_same<detail::PointerType<T>::type, T*>::value, \
                 "PointerType")
 #define EXPECT_IS_CAPTURED_AS_SCOPED_REFPTR(T)                        \
   static_assert(                                                      \
       is_same<detail::PointerType<T>::type, scoped_refptr<T>>::value, \
       "PointerType")
 
 EXPECT_IS_CAPTURED_AS_PTR(void);
 EXPECT_IS_CAPTURED_AS_PTR(int);
@@ skipping 125 matching lines @@
 // modified to a non-reference capture.
 TEST(BindTest, RefArgument) {
   const int x = 42;
   EXPECT_EQ(&x, Ref(x));
   // Bind() should make a copy of |x|, i.e. the pointers should be different.
   auto functor = Bind(&Ref, x);
   EXPECT_NE(&x, functor());
 }
 
 }  // namespace rtc