Revert of Replace scoped_ptr with unique_ptr in webrtc/common_audio/

webrtc/common_audio/fir_filter.cc

Index: webrtc/common_audio/fir_filter.cc
diff --git a/webrtc/common_audio/fir_filter.cc b/webrtc/common_audio/fir_filter.cc
index 13a2237dae1a599f737288d6752eae4cbbfd81d5..dc1b776f99728938cef7b684b96adaeb1a2b15cb 100644
--- a/webrtc/common_audio/fir_filter.cc
+++ b/webrtc/common_audio/fir_filter.cc
@@ -13,8 +13,7 @@
 #include <assert.h>
 #include <string.h>
 
-#include <memory>
-
+#include "webrtc/base/scoped_ptr.h"
 #include "webrtc/common_audio/fir_filter_neon.h"
 #include "webrtc/common_audio/fir_filter_sse.h"
 #include "webrtc/system_wrappers/include/cpu_features_wrapper.h"
@@ -31,8 +30,8 @@
  private:
   size_t coefficients_length_;
   size_t state_length_;
-  std::unique_ptr<float[]> coefficients_;
-  std::unique_ptr<float[]> state_;
+  rtc::scoped_ptr<float[]> coefficients_;
+  rtc::scoped_ptr<float[]> state_;
 };
 
 FIRFilter* FIRFilter::Create(const float* coefficients,