Fix namespace vs. node type issue in a generic way.

BUG=138673
Review URL: https://chromiumcodereview.appspot.com/10824157

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@149930 0039d316-1c4b-4281-b951-d872f2087c98

third_party/libxml/README.chromium

@@ -28,6 +28,8 @@ Modifications:
 - Add a fix for proper escaping of xpointer expressions, commit upstream is pending.
 - Add helper classes in chromium/libxml_utils.cc and chromium/include/libxml/libxml_utils.h.
 - Add a tweak to limit problems caused by excessive strings and buffers.
+- Change the xmlNs struct a little bit, so it looks like it has no children
+if treated as a generic xmlNode object.
 
 To import a new snapshot of libxml:
 

third_party/libxml/src/include/libxml/tree.h

@@ -351,6 +351,7 @@ struct _xmlNs {
     struct _xmlNs  *next;	/* next Ns link for this node  */
     xmlNsType      type;	/* global or local */
     const xmlChar *href;	/* URL for the namespace */
+    const char* dummy_children; /* lines up with node->children */
     const xmlChar *prefix;	/* prefix for the namespace */
     void           *_private;   /* application data */
     struct _xmlDoc *context;		/* normally an xmlDoc */