scoped_refptr add move constructor (#2284)

* scoped_refptr add move constructor

* scoped_refptr add move constructor

src/butil/memory/ref_counted.h

diff --git a/src/butil/memory/ref_counted.h b/src/butil/memory/ref_counted.h
index 5f01fc1..8fbb5d0 100644
--- a/src/butil/memory/ref_counted.h
+++ b/src/butil/memory/ref_counted.h
@@ -285,6 +285,21 @@
       ptr_->AddRef();
   }
 
+  scoped_refptr(scoped_refptr<T>&& r) noexcept {
+    if (r.ptr_){
+      ptr_ = r.ptr_;
+      r.ptr_ = nullptr;
+    }
+  }
+
+  template <typename U>
+  scoped_refptr(scoped_refptr<U>&& r) noexcept {
+    if (r.ptr_){
+      ptr_ = r.ptr_;
+      r.ptr_ = nullptr;
+    }
+  }
+ 
   ~scoped_refptr() {
     if (ptr_)
       ptr_->Release();