Part of fix for XALANJ-2294.  Given a node handle, the getDocumentRoot(int)
was returning the root of the current DTM.  It should be returning the root of
the DTM in which the particular node handle resides, which might be a different
DTM.

Reviewed by Christine Li (jycli () ca ! ibm ! com)

diff --git a/src/org/apache/xml/dtm/ref/DTMDefaultBase.java b/src/org/apache/xml/dtm/ref/DTMDefaultBase.java
index 896f07f..715383b 100644
--- a/src/org/apache/xml/dtm/ref/DTMDefaultBase.java
+++ b/src/org/apache/xml/dtm/ref/DTMDefaultBase.java
@@ -1608,7 +1608,7 @@
    */
   public int getDocumentRoot(int nodeHandle)
   {
-    return getDocument();
+    return getManager().getDTM(nodeHandle).getDocument();
   }
 
   /**