Use absl::make_unique and absl::WrapUnique directly

Instead of going through our wrappers in ptr_util.h.

This CL was generated by the following script:

  git grep -l ptr_util | xargs perl -pi -e 's,#include "rtc_base/ptr_util.h",#include "absl/memory/memory.h",'
  git grep -l MakeUnique | xargs perl -pi -e 's,\b(rtc::)?MakeUnique\b,absl::make_unique,g'
  git grep -l WrapUnique | xargs perl -pi -e 's,\b(rtc::)?WrapUnique\b,absl::WrapUnique,g'
  git checkout -- rtc_base/ptr_util{.h,_unittest.cc}
  git cl format

Followed by manually adding dependencies on
//third_party/abseil-cpp/absl/memory until `gn check` stopped
complaining.

Bug: webrtc:9473
Change-Id: I89ccd363f070479b8c431eb2c3d404a46eaacc1c
Reviewed-on: https://webrtc-review.googlesource.com/86600
Commit-Queue: Karl Wiberg <kwiberg@webrtc.org>
Reviewed-by: Danil Chapovalov <danilchap@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#23850}
diff --git a/rtc_base/testclient_unittest.cc b/rtc_base/testclient_unittest.cc
index dda1dae..b3a6c80 100644
--- a/rtc_base/testclient_unittest.cc
+++ b/rtc_base/testclient_unittest.cc
@@ -9,10 +9,10 @@
  */
 
 #include "rtc_base/testclient.h"
+#include "absl/memory/memory.h"
 #include "rtc_base/gunit.h"
 #include "rtc_base/nethelpers.h"
 #include "rtc_base/physicalsocketserver.h"
-#include "rtc_base/ptr_util.h"
 #include "rtc_base/testechoserver.h"
 #include "rtc_base/thread.h"
 
@@ -36,7 +36,7 @@
       main->socketserver()->CreateAsyncSocket(loopback.family(), SOCK_DGRAM);
   socket->Bind(loopback);
 
-  TestClient client(MakeUnique<AsyncUDPSocket>(socket));
+  TestClient client(absl::make_unique<AsyncUDPSocket>(socket));
   SocketAddress addr = client.address(), from;
   EXPECT_EQ(3, client.SendTo("foo", 3, addr));
   EXPECT_TRUE(client.CheckNextPacket("foo", 3, &from));
@@ -50,8 +50,8 @@
 
   AsyncSocket* socket =
       main->socketserver()->CreateAsyncSocket(loopback.family(), SOCK_STREAM);
-  std::unique_ptr<AsyncTCPSocket> tcp_socket =
-      WrapUnique(AsyncTCPSocket::Create(socket, loopback, server.address()));
+  std::unique_ptr<AsyncTCPSocket> tcp_socket = absl::WrapUnique(
+      AsyncTCPSocket::Create(socket, loopback, server.address()));
   ASSERT_TRUE(tcp_socket != nullptr);
 
   TestClient client(std::move(tcp_socket));