RefCounted types should not have public destructors

ppapi/proxy/var_serialization_rules.h

Index: ppapi/proxy/var_serialization_rules.h
diff --git a/ppapi/proxy/var_serialization_rules.h b/ppapi/proxy/var_serialization_rules.h
index bde9d4fad78cd71600465975cde5178e755c290a..399cff326ecf2dfc08233c94984f2c802a47ac2f 100644
--- a/ppapi/proxy/var_serialization_rules.h
+++ b/ppapi/proxy/var_serialization_rules.h
@@ -18,8 +18,6 @@ namespace proxy {
 // bookkeeping rules.
 class VarSerializationRules : public base::RefCounted<VarSerializationRules> {
  public:
-  virtual ~VarSerializationRules() {}
-
   // Caller-owned calls --------------------------------------------------------
   //
   // A caller-owned call is when doing a function call with a "normal" input
@@ -79,6 +77,10 @@ class VarSerializationRules : public base::RefCounted<VarSerializationRules> {
 
  protected:
   VarSerializationRules() {}
+  virtual ~VarSerializationRules() {}
+
+ private:
+  friend class base::RefCounted<VarSerializationRules>;
 };
 
 }  // namespace proxy