aCopy.mDOMRule = nsnull;   NS_ASSERTION(aDeclaration == aCopy.mDeclaration, "declaration mismatch"); aCopy.mSelector = nsnull; aCopy.mDeclaration = nsnull;
mDeclaration->AddRef();
CSSStyleRuleImpl::CSSStyleRuleImpl(CSSStyleRuleImpl& aCopy,                                   nsCSSDeclaration* aDeclaration)  : nsCSSRule(aCopy),    mSelector(aCopy.mSelector),    mDeclaration(aDeclaration),    mImportantRule(nsnull),    mDOMRule(aCopy.mDOMRule){  // The DOM rule is replacing |aCopy| with |this|, so transfer  // the reverse pointer as well (and transfer ownership).  aCopy.mDOMRule = nsnull;  // Transfer ownership of selector and declaration:  NS_ASSERTION(aDeclaration == aCopy.mDeclaration, "declaration mismatch");  aCopy.mSelector = nsnull;  aCopy.mDeclaration = nsnull;}