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/examples/objcnativeapi/objc/objccallclient.mm b/examples/objcnativeapi/objc/objccallclient.mm
index 7d9d78a..0e3b8e0 100644
--- a/examples/objcnativeapi/objc/objccallclient.mm
+++ b/examples/objcnativeapi/objc/objccallclient.mm
@@ -16,12 +16,12 @@
 #import <WebRTC/RTCVideoCodecFactory.h>
 #import <WebRTC/RTCVideoRenderer.h>
 
+#include "absl/memory/memory.h"
 #include "api/audio_codecs/builtin_audio_decoder_factory.h"
 #include "api/audio_codecs/builtin_audio_encoder_factory.h"
 #include "api/peerconnectioninterface.h"
 #include "media/engine/webrtcmediaengine.h"
 #include "modules/audio_processing/include/audio_processing.h"
-#include "rtc_base/ptr_util.h"
 #include "sdk/objc/Framework/Native/api/video_capturer.h"
 #include "sdk/objc/Framework/Native/api/video_decoder_factory.h"
 #include "sdk/objc/Framework/Native/api/video_encoder_factory.h"
@@ -56,7 +56,7 @@
 }  // namespace
 
 ObjCCallClient::ObjCCallClient()
-    : call_started_(false), pc_observer_(rtc::MakeUnique<PCObserver>(this)) {
+    : call_started_(false), pc_observer_(absl::make_unique<PCObserver>(this)) {
   thread_checker_.DetachFromThread();
   CreatePeerConnectionFactory();
 }