Merge DOMSettableTokensList into DOMTokensList

third_party/WebKit/LayoutTests/fast/dom/HTMLElement/script-tests/class-list.js

 description('Tests the classList attribute and its properties.');
 
 var element;
 
 function createElement(className)
 {
     element = document.createElement('p');
     element.className = className;
 }
 
 debug('Tests from http://simon.html5.org/test/html/dom/reflecting/DOMTokenList/');
 
-// http://simon.html5.org/test/html/dom/reflecting/DOMTokenList/setting/001.htm
-// Firefox throws here but WebKit does not throw on setting readonly idl
-// attributes.
+// Even though classList is readonly, PutForwards=value means that its value is forwarded.
 createElement('x');
 try {
     element.classList = 'y';
-    shouldBeEqualToString('String(element.classList)', 'x');
+    shouldBeEqualToString('String(element.classList)', 'y');
+    shouldBeEqualToString('String(element.className)', 'y');
 } catch (ex) {
-    testPassed('Throwing on set is acceptable');
+    testFailed('Throwing on set should not happen');
 }
 
 // http://simon.html5.org/test/html/dom/reflecting/DOMTokenList/getting/001.htm
 createElement('');
 shouldEvaluateTo('element.classList.length', 0);
 
 // http://simon.html5.org/test/html/dom/reflecting/DOMTokenList/getting/002.htm
 createElement('x');
 shouldEvaluateTo('element.classList.length', 1);
 
@@ skipping 337 matching lines @@
 element.classList.remove('a', 'c');
 shouldBe('observer.takeRecords().length', '1');
 
 // iterable<DOMString>;
 createElement('a b c');
 var seen = [];
 for (var t of element.classList) {
     seen.push(t);
 }
 shouldBeTrue("areArraysEqual(seen, ['a', 'b', 'c'])");