Description:
------------
Note that this is about the DOM extension, not DOM XML.

After using schemaValidate on a DOMDocument, the ID attributes should be marked, so getElementById() should work. This used to work in PHP 5.1.x, but is broken in current versions.

Reproduce code:
---------------
<?php
    $xml = <<<XML
<root>
  <item id="abc" />
  <item id="def" />
  <item id="xyz" />
</root>
XML;

    $schema = <<<XML
<?xml version="1.0"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" >
	<xs:element name="root">
		<xs:complexType>
			<xs:sequence>
				<xs:element name="item" type="item" maxOccurs="unbounded"/>
			</xs:sequence>
		</xs:complexType>
	</xs:element>
	
	<xs:complexType name="item">
		<xs:attribute name="id" use="required" type="xs:ID"/>
	</xs:complexType>
</xs:schema>
XML;

	$dom = new DOMDocument();
	$dom->loadXML($xml);
	if (!$dom->schemaValidateSource($schema)) trigger_error("Validation failed", E_USER_ERROR);

    $node = $dom->getElementById('def');
    echo $node ? 'Node found' : 'Where is it?';
?>

Expected result:
----------------
Node found

Actual result:
--------------
Where is it?