Support non-function object values assigned to EventHandler attributes

LayoutTests/fast/html/eventhandler-attribute-non-callable.html

Index: LayoutTests/fast/html/eventhandler-attribute-non-callable.html
diff --git a/LayoutTests/fast/html/eventhandler-attribute-non-callable.html b/LayoutTests/fast/html/eventhandler-attribute-non-callable.html
index 78ba7caf2e7699b55470007d04786c2c0c5fe31a..541fef525df527d0225a1ab4a8b32c33cb76b1af 100644
--- a/LayoutTests/fast/html/eventhandler-attribute-non-callable.html
+++ b/LayoutTests/fast/html/eventhandler-attribute-non-callable.html
@@ -33,10 +33,16 @@ shouldBe('callbackCount', '1');
 var o = { handleEvent: callback };
 shouldNotBe('div.onkeydown', 'null');
 shouldNotThrow('div.onkeydown = o');
-shouldBeNull('div.onkeydown');
+shouldBe('div.onkeydown', 'o');
 dispatchKeyEvent();
 shouldBe('callbackCount', '1');
 
+// Test non-object assignment.
+shouldNotThrow('div.onkeydown = callback');
+shouldBe('div.onkeydown', 'callback');
+shouldNotThrow('div.onkeydown = "non-object"');
+shouldBeNull('div.onkeydown');
+
 // Test null assignment.
 shouldNotThrow('div.onkeydown = callback');
 shouldBe('div.onkeydown', 'callback');