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}

modules/bitrate_controller/send_side_bandwidth_estimation.cc

@@ -16,12 +16,12 @@
 #include <limits>
 #include <string>
 
+#include "absl/memory/memory.h"
 #include "logging/rtc_event_log/events/rtc_event_bwe_update_loss_based.h"
 #include "logging/rtc_event_log/rtc_event_log.h"
 #include "modules/remote_bitrate_estimator/include/bwe_defines.h"
 #include "rtc_base/checks.h"
 #include "rtc_base/logging.h"
-#include "rtc_base/ptr_util.h"
 #include "system_wrappers/include/field_trial.h"
 #include "system_wrappers/include/metrics.h"
 
@@ -434,7 +434,7 @@ void SendSideBandwidthEstimation::CapBitrateToThresholds(int64_t now_ms,
   if (bitrate_bps != current_bitrate_bps_ ||
       last_fraction_loss_ != last_logged_fraction_loss_ ||
       now_ms - last_rtc_event_log_ms_ > kRtcEventLogPeriodMs) {
-    event_log_->Log(rtc::MakeUnique<RtcEventBweUpdateLossBased>(
+    event_log_->Log(absl::make_unique<RtcEventBweUpdateLossBased>(
         bitrate_bps, last_fraction_loss_,
         expected_packets_since_last_loss_update_));
     last_logged_fraction_loss_ = last_fraction_loss_;