function callback(error, stylePayload)
        {
            WebInspector.cssModel._pendingCommandsMajorState.pop();
            if (error) {
                if (userCallback)
                    userCallback(null);
                return;
            }
            WebInspector.domAgent.markUndoableState();
            if (userCallback) {
                var style = WebInspector.CSSStyleDeclaration.parsePayload(stylePayload);
                userCallback(style);
            }
        }
@param {string} newValue
@param {boolean} majorChange
@param {boolean} overwrite
@param {Function=} userCallback