Drop [LegacyInterfaceTypeChecking] where trivial in core/

third_party/WebKit/LayoutTests/fast/dom/TreeWalker/resources/TreeWalker-currentNode.js

 description("Tests the TreeWalker.")
 
 var subTree = document.createElement('div');
 subTree.innerHTML = "<p>Lorem ipsum <span>dolor <b>sit</b> amet</span>, consectetur <i>adipisicing</i> elit, sed do eiusmod <tt>tempor <b><i>incididunt ut</i> labore</b> et dolore magna</tt> aliqua.</p>"
 document.body.appendChild(subTree);
 
 var all = function(node) { return true; }
 var w = document.createTreeWalker(subTree, 0x01 | 0x08 | 0x10 | 0x20, all, true);
 
 debug("Test that TreeWalker.parent() doesn't set the currentNode to a node not under the root.");
 debug("");
 
 shouldBe("w.currentNode", "subTree");
 shouldBeNull("w.parentNode()");
 shouldBe("w.currentNode", "subTree");
 
 debug("");
+debug("Test that setting the currentNode to non-Node values throws.");
+debug("");
+
+shouldThrow("w.currentNode = null");
+shouldThrow("w.currentNode = {}");
+shouldThrow("w.currentNode = window");
+
+debug("");
 debug("Test that we handle setting the currentNode to arbitrary nodes not under the root element.");
 debug("");
 
 w.currentNode = document.documentElement;
 shouldBeNull("w.parentNode()");
 shouldBe("w.currentNode", "document.documentElement");
 w.currentNode = document.documentElement;
 shouldBe("w.nextNode()", "document.documentElement.firstChild");
 shouldBe("w.currentNode", "document.documentElement.firstChild");
 w.currentNode = document.documentElement;
@@ skipping 16 matching lines @@
 debug("Test how we handle the case when the traversed to node within the root, but the currentElement is not.");
 debug("");
 
 w.currentNode = subTree.previousSibling;
 shouldBe("w.nextNode()", "subTree");
 w.currentNode = document.body;
 shouldBe("w.lastChild()", "subTree");
 
 // Cleanup
 document.body.removeChild(subTree);