XmlView: configure top level element name

Allow the top level element name to be configured by setting
XmlView.RootNodeName.

lib/Cake/Test/Case/View/XmlViewTest.php

@@ -64,6 +64,13 @@ class XmlViewTest extends CakeTestCase {
 
 		$expected = Xml::build(array('response' => array('users' => $data)))->asXML();
 		$this->assertSame($expected, $output);
+
+		$Controller->set('_rootNode', 'custom_name');
+		$View = new XmlView($Controller);
+		$output = $View->render(false);
+
+		$expected = Xml::build(array('custom_name' => array('users' => $data)))->asXML();
+		$this->assertSame($expected, $output);
 	}
 
 /**
@@ -79,13 +86,20 @@ class XmlViewTest extends CakeTestCase {
 		$Controller->set($data);
 		$Controller->set('_serialize', array('no', 'user'));
 		$View = new XmlView($Controller);
+		$this->assertSame('application/xml', $Response->type());
 		$output = $View->render(false);
-
 		$expected = array(
 			'response' => array('no' => $data['no'], 'user' => $data['user'])
 		);
 		$this->assertSame(Xml::build($expected)->asXML(), $output);
-		$this->assertSame('application/xml', $Response->type());
+
+		$Controller->set('_rootNode', 'custom_name');
+		$View = new XmlView($Controller);
+		$output = $View->render(false);
+		$expected = array(
+			'custom_name' => array('no' => $data['no'], 'user' => $data['user'])
+		);
+		$this->assertSame(Xml::build($expected)->asXML(), $output);
 	}
 
 /**

lib/Cake/View/XmlView.php

@@ -99,15 +99,17 @@ class XmlView extends View {
  * @return string The serialized data
  */
 	protected function _serialize($serialize) {
+		$rootNode = isset($this->viewVars['_rootNode']) ? $this->viewVars['_rootNode'] : 'response';
+
 		if (is_array($serialize)) {
-			$data = array('response' => array());
+			$data = array($rootNode => array());
 			foreach ($serialize as $key) {
-				$data['response'][$key] = $this->viewVars[$key];
+				$data[$rootNode][$key] = $this->viewVars[$key];
 			}
 		} else {
 			$data = isset($this->viewVars[$serialize]) ? $this->viewVars[$serialize] : null;
 			if (is_array($data) && Set::numeric(array_keys($data))) {
-				$data = array('response' => array($serialize => $data));
+				$data = array($rootNode => array($serialize => $data));
 			}
 		}
 		 return Xml::fromArray($data)->asXML();