Update Custom Elements API to new names.

LayoutTests/fast/dom/custom/registration-context-sharing.html

Index: LayoutTests/fast/dom/custom/registration-context-sharing.html
diff --git a/LayoutTests/fast/dom/custom/registration-context-sharing.html b/LayoutTests/fast/dom/custom/registration-context-sharing.html
index 98d4ea60aae1aa4c5441b1c951ae9c04a590961f..50e2d8811afc83979edaf5b614968070124e09d6 100644
--- a/LayoutTests/fast/dom/custom/registration-context-sharing.html
+++ b/LayoutTests/fast/dom/custom/registration-context-sharing.html
@@ -33,7 +33,7 @@ testUpgrade_oneDefinitionShouldUpgradeMultipleDocuments = function () {
     var protoU = Object.create(this.window.HTMLElement.prototype);
     protoU.prototypeTag = 'U';
     protoU.createdCallback = created;
-    this.documentB.register('x-u', {prototype: protoU});
+    this.documentB.registerElement('x-u', {prototype: protoU});
 
     assert_array_equals(
         invocations,
@@ -54,7 +54,7 @@ testRegisterInAInstantiateInB_shouldActivateDefinition = function () {
     var protoV = Object.create(this.window.HTMLElement.prototype);
     protoV.prototypeTag = 'V';
     protoV.createdCallback = created;
-    this.documentA.register('x-v', {prototype: protoV});
+    this.documentA.registerElement('x-v', {prototype: protoV});
 
     var div = this.documentB.createElement('div');
     div.innerHTML = '<x-v data-name="document B element V"></x-v>';