Remove rtc::{Make,Wrap}Unique and their header file + unit tests

We've switched to absl::make_unique and absl::WrapUnique.

Bug: webrtc:9473
Change-Id: I08aef72d52b571c511c0f4adb4c68d6cc2654192
Reviewed-on: https://webrtc-review.googlesource.com/87262
Commit-Queue: Karl Wiberg <kwiberg@webrtc.org>
Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#24225}

sdk/android/src/jni/androidmediadecoder.cc

@@ -23,7 +23,6 @@
 #include "rtc_base/checks.h"
 #include "rtc_base/logging.h"
 #include "rtc_base/numerics/safe_conversions.h"
-#include "rtc_base/ptr_util.h"
 #include "rtc_base/scoped_ref_ptr.h"
 #include "rtc_base/thread.h"
 #include "rtc_base/timeutils.h"

sdk/android/src/jni/androidmediaencoder.cc

@@ -30,7 +30,6 @@
 #include "rtc_base/bind.h"
 #include "rtc_base/checks.h"
 #include "rtc_base/logging.h"
-#include "rtc_base/ptr_util.h"
 #include "rtc_base/sequenced_task_checker.h"
 #include "rtc_base/task_queue.h"
 #include "rtc_base/thread.h"

sdk/android/src/jni/pc/video.cc

@@ -18,7 +18,6 @@
 #include "api/videosourceproxy.h"
 #include "media/engine/convert_legacy_video_factory.h"
 #include "rtc_base/logging.h"
-#include "rtc_base/ptr_util.h"
 #include "sdk/android/src/jni/androidvideotracksource.h"
 #include "sdk/android/src/jni/videodecoderfactorywrapper.h"
 #include "sdk/android/src/jni/videoencoderfactorywrapper.h"