Tests the interfaces of the highlight API, which include Highlight, HighlightRegister, and extensions to the CSS namespace. On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE". Testing Highlight: PASS Highlight instanceof Function is true PASS typeof Highlight is "function" PASS new Highlight(new StaticRange({startContainer: document.body, startOffset: 1, endContainer: document.body, endOffset: 2})) instanceof Highlight is true PASS HighlightRegister instanceof Function is true PASS typeof HighlightRegister is "function" PASS new HighlightRegister() instanceof HighlightRegister is true PASS new HighlightRegister().set("foo-styling",new Highlight(new StaticRange({startContainer: document.body, startOffset: 1, endContainer: document.body, endOffset: 2}))) is defined. PASS CSS.highlights is defined. PASS CSS.highlights.set("foo-styling",new Highlight(new StaticRange({startContainer: document.body, startOffset: 1, endContainer: document.body, endOffset: 2}))) is CSS.highlights PASS successfullyParsed is true TEST COMPLETE