Update Custom Elements API to new names.

LayoutTests/fast/dom/custom/isolated-world.html

Index: LayoutTests/fast/dom/custom/isolated-world.html
diff --git a/LayoutTests/fast/dom/custom/isolated-world.html b/LayoutTests/fast/dom/custom/isolated-world.html
index 3f79bb28880a12f5e090f3140731c5c1b95ef0f7..61d08d12ee6c0f120e8ea0e00cc74972ac8b7723 100644
--- a/LayoutTests/fast/dom/custom/isolated-world.html
+++ b/LayoutTests/fast/dom/custom/isolated-world.html
@@ -28,7 +28,7 @@ result = testRunner.evaluateScriptInIsolatedWorldAndReturnValue(
     '    console.log(this.id + " entered (isolated)"); ' +
     '  }; ' +
     '  try { ' +
-    '    document.register("x-a", {extends: "span", prototype: proto}); ' +
+    '    document.registerElement("x-a", {extends: "span", prototype: proto}); ' +
     '    return "register succeeded"; ' +
     '  } catch (e) { ' +
     '    return e.code; ' +
@@ -47,10 +47,10 @@ shouldBe('a.__proto__', 'HTMLSpanElement.prototype',
 
 var proto = Object.create(HTMLSpanElement.prototype);
 invocations = [];
-proto.enteredViewCallback = function () {
+proto.attachedCallback = function () {
     invocations.push(this.id + ' entered (main)');
 };
-document.register('x-a', {extends: 'span', prototype: proto});
+document.registerElement('x-a', {extends: 'span', prototype: proto});
 shouldBe('invocations', '["y entered (main)"]',
          'only the element in the document should generate entered events');