base: Use std::move() instead of Pass() for real movable types.

base/memory/ref_counted.h

Index: base/memory/ref_counted.h
diff --git a/base/memory/ref_counted.h b/base/memory/ref_counted.h
index 5f94b4c37ae2eb510176b585b30a9af20e216d32..26c65519664ee0eddb8cf7d2c8687232f8ec36f1 100644
--- a/base/memory/ref_counted.h
+++ b/base/memory/ref_counted.h
@@ -331,13 +331,13 @@ class scoped_refptr {
   }
 
   scoped_refptr<T>& operator=(scoped_refptr<T>&& r) {
-    scoped_refptr<T>(r.Pass()).swap(*this);
+    scoped_refptr<T>(std::move(r)).swap(*this);
     return *this;
   }
 
   template <typename U>
   scoped_refptr<T>& operator=(scoped_refptr<U>&& r) {
-    scoped_refptr<T>(r.Pass()).swap(*this);
+    scoped_refptr<T>(std::move(r)).swap(*this);
     return *this;
   }