Tests that proper source lines are reported for the parsed styles.

[expanded] 
element.style  { ()

======== Matched CSS Rules ========
[expanded] 
media="screen" (styles-source-lines.html)
#main, .at_line_50  { (styles-source-lines.html:50)
border: 1px solid
    red;

[expanded] 
media="screen" (styles-source-lines.html)
#main, .at_line_43  { (styles-source-lines.html:43)
font-size: 10px;

[expanded] 
media="screen" (styles-source-lines.html)
#main, .at_line_29  { (styles-source-lines.html:29)
font-family: /*  Comment in 
                      value  */courier;

[expanded] 
media="screen" (styles-source-lines.html)
#main, .at_line_15::before  { (styles-source-lines.html:15)
color: red;
content: "Before";

[expanded] 
div  { (user agent stylesheet)
display: block;