Replace scoped_ptr with unique_ptr in webrtc/modules/audio_processing/transient/

BUG=webrtc:5520

Review URL: https://codereview.webrtc.org/1698843003

Cr-Commit-Position: refs/heads/master@{#11645}
diff --git a/webrtc/modules/audio_processing/transient/wpd_node.h b/webrtc/modules/audio_processing/transient/wpd_node.h
index f66cad9..99521fd 100644
--- a/webrtc/modules/audio_processing/transient/wpd_node.h
+++ b/webrtc/modules/audio_processing/transient/wpd_node.h
@@ -11,7 +11,8 @@
 #ifndef WEBRTC_MODULES_AUDIO_PROCESSING_TRANSIENT_WPD_NODE_H_
 #define WEBRTC_MODULES_AUDIO_PROCESSING_TRANSIENT_WPD_NODE_H_
 
-#include "webrtc/base/scoped_ptr.h"
+#include <memory>
+
 #include "webrtc/typedefs.h"
 
 namespace webrtc {
@@ -36,9 +37,9 @@
   size_t length() const { return length_; }
 
  private:
-  rtc::scoped_ptr<float[]> data_;
+  std::unique_ptr<float[]> data_;
   size_t length_;
-  rtc::scoped_ptr<FIRFilter> filter_;
+  std::unique_ptr<FIRFilter> filter_;
 };
 
 }  // namespace webrtc