// Don't continue if errors exist
checkErrors();
CollectConstantDefinitions collectConstantDefinitionsPass = new CollectConstantDefinitions(
cssTree);
collectConstantDefinitionsPass.runPass();
ReplaceConstantReferences replaceConstantReferences = new ReplaceConstantReferences(cssTree,
collectConstantDefinitionsPass.getConstantDefinitions(), true, errorManager, false);
replaceConstantReferences.runPass();