--- a/xpcom/glue/nsISupportsImpl.h
+++ b/xpcom/glue/nsISupportsImpl.h
@@ -522,48 +522,58 @@ public:                                 
     }                                                                         \
     return mRefCnt;                                                           \
   }                                                                           \
 protected:                                                                    \
   nsAutoRefCnt mRefCnt;                                                       \
   NS_DECL_OWNINGTHREAD                                                        \
 public:
 
-/**
- * Use this macro to declare and implement the AddRef & Release methods for a
- * given non-XPCOM <i>_class</i> in a threadsafe manner.
- *
- * DOES NOT DO REFCOUNT STABILIZATION!
- *
- * @param _class The name of the class implementing the method
- */
-#define NS_INLINE_DECL_THREADSAFE_REFCOUNTING(_class, ...)                    \
+#define NS_INLINE_DECL_THREADSAFE_REFCOUNTING_META(_class, _decl, ...)        \
 public:                                                                       \
-  NS_METHOD_(MozExternalRefCountType) AddRef(void) __VA_ARGS__ {              \
+  _decl(MozExternalRefCountType) AddRef(void) __VA_ARGS__ {                   \
     MOZ_ASSERT_TYPE_OK_FOR_REFCOUNTING(_class)                                \
     MOZ_ASSERT(int32_t(mRefCnt) >= 0, "illegal refcnt");                      \
     nsrefcnt count = ++mRefCnt;                                               \
     NS_LOG_ADDREF(this, count, #_class, sizeof(*this));                       \
     return (nsrefcnt) count;                                                  \
   }                                                                           \
-  NS_METHOD_(MozExternalRefCountType) Release(void) __VA_ARGS__ {             \
+  _decl(MozExternalRefCountType) Release(void) __VA_ARGS__ {                  \
     MOZ_ASSERT(int32_t(mRefCnt) > 0, "dup release");                          \
     nsrefcnt count = --mRefCnt;                                               \
     NS_LOG_RELEASE(this, count, #_class);                                     \
     if (count == 0) {                                                         \
       delete (this);                                                          \
       return 0;                                                               \
     }                                                                         \
     return count;                                                             \
   }                                                                           \
 protected:                                                                    \
   ::mozilla::ThreadSafeAutoRefCnt mRefCnt;                                    \
 public:
 
 /**
+ * Use this macro to declare and implement the AddRef & Release methods for a
+ * given non-XPCOM <i>_class</i> in a threadsafe manner.
+ *
+ * DOES NOT DO REFCOUNT STABILIZATION!
+ *
+ * @param _class The name of the class implementing the method
+ */
+#define NS_INLINE_DECL_THREADSAFE_REFCOUNTING(_class, ...)                    \
+NS_INLINE_DECL_THREADSAFE_REFCOUNTING_META(_class, NS_METHOD_, __VA_ARGS__)
+
+/**
+ * Like NS_INLINE_DECL_THREADSAFE_REFCOUNTING with AddRef & Release declared
+ * virtual.
+ */
+#define NS_INLINE_DECL_THREADSAFE_VIRTUAL_REFCOUNTING(_class, ...)            \
+NS_INLINE_DECL_THREADSAFE_REFCOUNTING_META(_class, NS_IMETHOD_, __VA_ARGS__)
+
+/**
  * Use this macro to implement the AddRef method for a given <i>_class</i>
  * @param _class The name of the class implementing the method
  */
 #define NS_IMPL_ADDREF(_class)                                                \
 NS_IMETHODIMP_(MozExternalRefCountType) _class::AddRef(void)                  \
 {                                                                             \
   MOZ_ASSERT_TYPE_OK_FOR_REFCOUNTING(_class)                                  \
   MOZ_ASSERT(int32_t(mRefCnt) >= 0, "illegal refcnt");                        \