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/modules/rtp_rtcp/source/rtcp_transceiver_impl.cc b/modules/rtp_rtcp/source/rtcp_transceiver_impl.cc
index 5cfe019..a4da63a 100644
--- a/modules/rtp_rtcp/source/rtcp_transceiver_impl.cc
+++ b/modules/rtp_rtcp/source/rtcp_transceiver_impl.cc
@@ -12,6 +12,7 @@
 
 #include <utility>
 
+#include "absl/memory/memory.h"
 #include "api/call/transport.h"
 #include "api/video/video_bitrate_allocation.h"
 #include "modules/rtp_rtcp/include/receive_statistics.h"
@@ -30,7 +31,6 @@
 #include "modules/rtp_rtcp/source/time_util.h"
 #include "rtc_base/checks.h"
 #include "rtc_base/logging.h"
-#include "rtc_base/ptr_util.h"
 #include "rtc_base/task_queue.h"
 #include "rtc_base/timeutils.h"
 
@@ -334,7 +334,7 @@
       if (!ptr_)
         return true;
       ptr_->SendPeriodicCompoundPacket();
-      task_queue_->PostDelayedTask(rtc::WrapUnique(this),
+      task_queue_->PostDelayedTask(absl::WrapUnique(this),
                                    ptr_->config_.report_period_ms);
       return false;
     }
@@ -346,7 +346,7 @@
 
   RTC_DCHECK(config_.schedule_periodic_compound_packets);
 
-  auto task = rtc::MakeUnique<SendPeriodicCompoundPacketTask>(
+  auto task = absl::make_unique<SendPeriodicCompoundPacketTask>(
       config_.task_queue, ptr_factory_.GetWeakPtr());
   if (delay_ms > 0)
     config_.task_queue->PostDelayedTask(std::move(task), delay_ms);