Add MakeUnique from chromium and change StunMessage::AddAttribute to take a unique_ptr.

webrtc/base/ptr_util_unittest.cc

+/*
+ *  Copyright 2017 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 "webrtc/base/ptr_util.h"
+
+#include <stddef.h>
+#include <string>
+
+#include "webrtc/base/gunit.h"
+
+namespace rtc {
+
+namespace {
+
+class DeleteCounter {
+ public:
+  DeleteCounter() { ++count_; }
+  ~DeleteCounter() { --count_; }
+
+  static size_t count() { return count_; }
+
+ private:
+  static size_t count_;
+};
+
+size_t DeleteCounter::count_ = 0;
+
+}  // namespace
+
+TEST(PtrUtilTest, WrapUnique) {
+  EXPECT_EQ(0u, DeleteCounter::count());
+  DeleteCounter* counter = new DeleteCounter;
+  EXPECT_EQ(1u, DeleteCounter::count());
+  std::unique_ptr<DeleteCounter> owned_counter = WrapUnique(counter);
+  EXPECT_EQ(1u, DeleteCounter::count());
+  owned_counter.reset();
+  EXPECT_EQ(0u, DeleteCounter::count());
+}
+
+TEST(PtrUtilTest, MakeUniqueScalar) {
+  auto s = MakeUnique<std::string>();
+  EXPECT_EQ("", *s);
+
+  auto s2 = MakeUnique<std::string>("test");
+  EXPECT_EQ("test", *s2);
+}
+
+TEST(PtrUtilTest, MakeUniqueScalarWithMoveOnlyType) {
+  using MoveOnly = std::unique_ptr<std::string>;
+  auto p = MakeUnique<MoveOnly>(MakeUnique<std::string>("test"));
+  EXPECT_EQ("test", **p);
+}
+
+TEST(PtrUtilTest, MakeUniqueArray) {
+  EXPECT_EQ(0u, DeleteCounter::count());
+  auto a = MakeUnique<DeleteCounter[]>(5);
+  EXPECT_EQ(5u, DeleteCounter::count());
+  a.reset();
+  EXPECT_EQ(0u, DeleteCounter::count());
+}
+
+}  // namespace rtc