Revert of skstd -> std for unique_ptr

include/core/SkRefCnt.h

Index: include/core/SkRefCnt.h
diff --git a/include/core/SkRefCnt.h b/include/core/SkRefCnt.h
index 1779278c6f889b920d81158266baaf970def088c..9d1e5f1f02c252c13c2091208903457403c0a825 100644
--- a/include/core/SkRefCnt.h
+++ b/include/core/SkRefCnt.h
@@ -9,8 +9,8 @@
 #define SkRefCnt_DEFINED
 
 #include "../private/SkAtomics.h"
+#include "../private/SkUniquePtr.h"
 #include "SkTypes.h"
-#include <memory>
 
 /** \class SkRefCntBase
 
@@ -185,22 +185,12 @@
 /**
  *  Utility class that simply unref's its argument in the destructor.
  */
-template <typename T> class SkAutoTUnref {
-public:
-    explicit SkAutoTUnref(T* obj = nullptr) : fPtr(obj) {}
-
-    void swap(SkAutoTUnref& other) { fPtr.swap(other.fPtr); }
-
-    T*        get() const { return fPtr.get(); }
-    operator T*  () const { return fPtr.get(); }
-    T* operator->() const { return fPtr.get(); }
-
-    void reset(T* ptr = nullptr) { fPtr.reset(ptr); }
-    T* detach()  { return fPtr.release(); }
-    T* release() { return fPtr.release(); }
-
-private:
-    std::unique_ptr<T, SkTUnref<T>> fPtr;
+template <typename T> class SkAutoTUnref : public skstd::unique_ptr<T, SkTUnref<T>> {
+public:
+    explicit SkAutoTUnref(T* obj = nullptr) : skstd::unique_ptr<T, SkTUnref<T>>(obj) {}
+
+    T* detach() { return this->release(); }
+    operator T*() const { return this->get(); }
 };
 // Can't use the #define trick below to guard a bare SkAutoTUnref(...) because it's templated. :(