Tests DOM.getContentQuads method with text inside display:contents elements.
{
    result : {
        className : HTMLAnchorElement
        description : a
        objectId : <string>
        subtype : node
        type : object
    }
}
Returned quads count: 1
{
    result : {
        className : HTMLElement
        description : b
        objectId : <string>
        subtype : node
        type : object
    }
}
Returned quads count: 1