Replace scoped_ptr with unique_ptr in webrtc/modules/

Except in places where this would break out-of-tree code,
such as Chromium.

BUG=webrtc:5520

Review URL: https://codereview.webrtc.org/1785173002

Cr-Commit-Position: refs/heads/master@{#12037}
diff --git a/webrtc/modules/utility/source/coder.h b/webrtc/modules/utility/source/coder.h
index abfa87e..399edbd 100644
--- a/webrtc/modules/utility/source/coder.h
+++ b/webrtc/modules/utility/source/coder.h
@@ -11,7 +11,8 @@
 #ifndef WEBRTC_MODULES_UTILITY_SOURCE_CODER_H_
 #define WEBRTC_MODULES_UTILITY_SOURCE_CODER_H_
 
-#include "webrtc/base/scoped_ptr.h"
+#include <memory>
+
 #include "webrtc/common_types.h"
 #include "webrtc/modules/audio_coding/include/audio_coding_module.h"
 #include "webrtc/typedefs.h"
@@ -46,7 +47,7 @@
                   const RTPFragmentationHeader* fragmentation) override;
 
 private:
- rtc::scoped_ptr<AudioCodingModule> _acm;
+ std::unique_ptr<AudioCodingModule> _acm;
 
     CodecInst _receiveCodec;