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/audio_coding/neteq/tools/rtp_encode.cc b/modules/audio_coding/neteq/tools/rtp_encode.cc
index 1984e3f..abbb621 100644
--- a/modules/audio_coding/neteq/tools/rtp_encode.cc
+++ b/modules/audio_coding/neteq/tools/rtp_encode.cc
@@ -21,6 +21,7 @@
 #include <map>
 #include <string>
 
+#include "absl/memory/memory.h"
 #include "api/audio/audio_frame.h"
 #include "api/audio_codecs/L16/audio_encoder_L16.h"
 #include "api/audio_codecs/g711/audio_encoder_g711.h"
@@ -33,7 +34,6 @@
 #include "modules/audio_coding/neteq/tools/input_audio_file.h"
 #include "rtc_base/flags.h"
 #include "rtc_base/numerics/safe_conversions.h"
-#include "rtc_base/ptr_util.h"
 #include "typedefs.h"  // NOLINT(build/include)
 
 namespace webrtc {
@@ -313,7 +313,7 @@
     AudioEncoderCng::Config cng_config = GetCngConfig(codec->SampleRateHz());
     RTC_DCHECK(codec);
     cng_config.speech_encoder = std::move(codec);
-    codec = rtc::MakeUnique<AudioEncoderCng>(std::move(cng_config));
+    codec = absl::make_unique<AudioEncoderCng>(std::move(cng_config));
   }
   RTC_DCHECK(codec);