GTTF: Add a basic new unit test launcher.

third_party/libxml/chromium/libxml_utils.h

Index: third_party/libxml/chromium/libxml_utils.h
diff --git a/third_party/libxml/chromium/libxml_utils.h b/third_party/libxml/chromium/libxml_utils.h
index 80d05f67d8df1a66fe3b5fe280af96fb34fbabd7..9091f491b48d9018e6c40534ec7119762b469e72 100644
--- a/third_party/libxml/chromium/libxml_utils.h
+++ b/third_party/libxml/chromium/libxml_utils.h
@@ -73,6 +73,9 @@ class XmlReader {
   // returns true and |value| is set to "a".
   bool NodeAttribute(const char* name, std::string* value);
 
+  // Returns true if the node is a closing element (e.g. </foo>).
+  bool IsClosingElement();
+
   // Helper functions not provided by libxml ----------------------------------
 
   // Return the string content within an element.