ScriptValueSerializer should throw, not crash, when handling unknown types

LayoutTests/fast/js/structured-clone.html

Index: LayoutTests/fast/js/structured-clone.html
diff --git a/LayoutTests/fast/js/structured-clone.html b/LayoutTests/fast/js/structured-clone.html
index 43796941ca9969fc0eff4ad1e104329299396b21..913744e919086b606a9962e013260330ef823c04 100644
--- a/LayoutTests/fast/js/structured-clone.html
+++ b/LayoutTests/fast/js/structured-clone.html
@@ -205,4 +205,13 @@ promise_test(function() {
     });
 }, 'Cloning Sets should fail if they contain non-cloneable things');
 
+promise_test(function() {
+    return structuredClone(Symbol('foo')).then(function(clone) {
+        assert_unreached('Should have thrown an exception');
+    }).catch(function(ex) {

[jsbell, 2015/08/19 01:24:11]

I believe this will 'catch' the exception thrown by assert_unreached; you'll
want to use the two-argument form of then() so a failing assert here will make
it to the end of the promise chain.

(Which means the cases above for Map and Set are wrong too?)

[adamk, 2015/08/19 20:19:34]

Fixed here and above to use the two-arg then().

+        assert_true(ex instanceof DOMException, 'Should throw a DOMException');
+        assert_equals(ex.code, DOMException.DATA_CLONE_ERR, 'Should be a DataCloneError');
+    });
+}, 'Cloning Symbols should fail');
+
 </script>