Adds equality operators for comparing scoped_refptr with nullptr.

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 0c0e0afd770f4bb3f71d222b098d200c4e3688d4..dfe66d6e0351ea94f915eecaca4b3d9b8560542f 100644
--- a/base/memory/ref_counted.h
+++ b/base/memory/ref_counted.h
@@ -5,6 +5,8 @@
 #ifndef BASE_MEMORY_REF_COUNTED_H_
 #define BASE_MEMORY_REF_COUNTED_H_
 
+#include <stddef.h>
+
 #include <cassert>
 #include <iosfwd>
 #include <type_traits>
@@ -441,6 +443,16 @@ bool operator==(const T* lhs, const scoped_refptr<U>& rhs) {
   return lhs == rhs.get();
 }
 
+template <typename T>
+bool operator==(const scoped_refptr<T>& lhs, std::nullptr_t null) {
+  return !static_cast<bool>(lhs);
+}
+
+template <typename T>
+bool operator==(std::nullptr_t null, const scoped_refptr<T>& rhs) {
+  return !static_cast<bool>(rhs);
+}
+
 template <typename T, typename U>
 bool operator!=(const scoped_refptr<T>& lhs, const U* rhs) {
   return !operator==(lhs, rhs);
@@ -452,6 +464,16 @@ bool operator!=(const T* lhs, const scoped_refptr<U>& rhs) {
 }
 
 template <typename T>
+bool operator!=(const scoped_refptr<T>& lhs, std::nullptr_t null) {
+  return !operator==(lhs, null);
+}
+
+template <typename T>
+bool operator!=(std::nullptr_t null, const scoped_refptr<T>& rhs) {
+  return !operator==(null, rhs);
+}
+
+template <typename T>
 std::ostream& operator<<(std::ostream& out, const scoped_refptr<T>& p) {
   return out << p.get();
 }