static GroupId calculateGroupId(StyleBase* styleBase)
{
    ASSERT(styleBase);
    StyleBase* current = styleBase;
    StyleSheet* styleSheet = 0;
    while (true) {
        // Special case: CSSStyleDeclarations might be either inline and in this case
        // we need to group them with their node or regular ones.
        if (current->isMutableStyleDeclaration()) {
            CSSMutableStyleDeclaration* cssMutableStyleDeclaration = static_cast<CSSMutableStyleDeclaration*>(current);
            if (cssMutableStyleDeclaration->isInlineStyleDeclaration()) {
                ASSERT(cssMutableStyleDeclaration->parent()->isStyleSheet());
                return calculateGroupId(cssMutableStyleDeclaration->node());
            }
            // Either we have no parent, or this parent is a CSSRule.
            ASSERT(cssMutableStyleDeclaration->parent() == cssMutableStyleDeclaration->parentRule());
        }

        if (current->isStyleSheet())
            styleSheet = static_cast<StyleSheet*>(current);

        StyleBase* parent = current->parent();
        if (!parent)
            break;
        current = parent;
    }

    if (styleSheet) {
        if (Node* ownerNode = styleSheet->ownerNode())
            return calculateGroupId(ownerNode);
        return GroupId(styleSheet);
    }

    return GroupId(current);
}
CSSMutableStyleDeclaration* CSSVariablesDeclaration::getParsedVariableDeclarationBlock(const String& variableName)
{
    StyleBase* result = m_variablesMap.get(variableName).get();
    if (result->isMutableStyleDeclaration())
        return static_cast<CSSMutableStyleDeclaration*>(result);
    return 0;
}
CSSMutableStyleDeclaration* CSSVariablesDeclaration::getParsedVariableDeclarationBlock(const String&)
{
// FIXME: Disabling declarations as variable values for now since they no longer have a common base class with CSSValues.
#if 0
    StyleBase* result = m_variablesMap.get(variableName).get();

    if (result->isMutableStyleDeclaration())
        return static_cast<CSSMutableStyleDeclaration*>(result);
#endif
    return 0;
}