nsDOMCSSDeclaration has NS_DECL_ISUPPORTS, so gets an mRefCnt member. DOMCSSDeclarationImpl inherits from nsDOMCSSDeclaration but DOMCSSDeclarationImpl overrides addref/release to aggregate with its style rule, which means that DOMCSSDeclarationImpl has an unused mRefCnt member. The NS_DECL_ISUPPORTS should be pushed down into nsDOMCSSAttrDeclaration, and nsDOMCSSDeclaration will just have some pure virtual methods, which is fine -- we don't want anyone instantiating objects of that class anyway.
Comment on attachment 129560 [details] [diff] [review] proposed patch >+ NS_DECL_ISUPPORTS Could you expand this, and skip the QueryInterface. I object to the existence of NS_IMPL_QUERY_INTERFACE_INHERITED0. >+NS_IMPL_ADDREF(nsDOMCSSAttributeDeclaration); >+NS_IMPL_RELEASE(nsDOMCSSAttributeDeclaration); No need for semicolons.
Created attachment 129561 [details] [diff] [review] Patch updated to comments