Tests SourceMap and StyleSheetMapping.

Added CSS uiSourceCode: http://127.0.0.1:8000/devtools/resources/example.css
Added SCSS uiSourceCode: http://127.0.0.1:8000/devtools/resources/example.scss
0:3 0:3(expected: 0:3) -> 0:3
1:0 1:0(expected: 1:0) -> 1:0
2:4 2:2(expected: 2:2) -> 2:2
2:6 2:5(expected: 2:5) -> 2:5
2:9 2:7(expected: 2:7) -> 2:7
3:7 2:10(expected: 2:10) -> 2:10
4:8 4:2(expected: 4:2) -> 4:2
4:10 4:2(expected: 4:2) -> 4:2
4:11 4:11(expected: 4:11) -> 4:11
4:15 4:13(expected: 4:13) -> 4:13
4:20 4:17(expected: 4:17) -> 4:17
UILocation upon LiveLocation update: http://127.0.0.1:8000/devtools/resources/example.scss:2:2