Move libxml_utils from chrome/common to third_party/libxml/chromium.

third_party/libxml/README.chromium

 Name: libxml
 URL: http://xmlsoft.org
 Version: 2.7.7
 License File: src/COPYING
 Security Critical: yes
 
 Description:
 The src/ directory contains a partial snapshot of the libxml library
 with the patches in the patches/ directories applied.
 See the files in that directory for discussion of their effects.
 
 Current version: 2.7.7.
 
 Modifications:
 - Import XPath fix http://git.gnome.org/browse/libxml2/commit/?id=91d19754d46acd4a639a8b9e31f50f31c78f8c9c
 - Import follow-on for above commit: http://git.gnome.org/browse/libxml2/commit/?id=ea90b894146030c214a7df6d8375310174f134b9
 - Import additional XPath fix http://git.gnome.org/browse/libxml2/commit/?id=df83c17e5a2646bd923f75e5e507bc80d73c9722
 - Import follow-on fix for above commit: http://git.gnome.org/browse/libxml2/commit/?id=fec31bcd452e77c10579467ca87a785b41115de6
 - And a follow-on fix to the previous two fixes, committed upstream: http://git.gnome.org/browse/libxml2/commit/?id=f5048b3e71fc30ad096970b8df6e7af073bae4cb (slightly differently, but we can drop our local fix on the next roll).
 - Add a fix for handling of unknown namespaces, commit upstream is pending.
 - Add fixes for ending the parse properly if a SAX callback calls xmlStopParser(), commit upstream is pending.
 - Add fix for entities, commit upstream is http://git.gnome.org/browse/libxml2/commit/?id=5bd3c061823a8499b27422aee04ea20aae24f03e
 - Import UTF-8 fix from upstream: http://git.gnome.org/browse/libxml2/commit/?id=0795348aeb86648723bc391e4d02e20631c10bca 
 - Import XPath fix http://git.gnome.org/browse/libxml2/commit/xpath.c?id=2ddecc23862bab1a9a9e51e097aefc92ec305e28
 - Merge clang warning fix http://git.gnome.org/browse/libxml2/commit/?id=aae48e64dfbf2b46b157a4c1857e30645116388f
 - 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.
 
 To import a new snapshot of libxml:
 
 - Visit http://xmlsoft.org/downloads.html and download the latest source
   distribution.
 - Copy the files into this directory, omitting files which have been omitted
   here.  E.g.:  for i in $(find . -type f); do cp ../libxml-newver/$i $i; done
   This should clobber all local changes to this directory.
 - Apply the patches in patches/ and fix any problems.
   UPDATE THOSE PATCHES OR EVAN WILL HUNT YOU DOWN.
 - On a Linux system,
     $ cd linux
     $ ../configure --without-iconv --without-ftp --without-http
   to generate config.h and include/libxml/xmlversion.h for Linux.
 - On a Mac,
     $ cd mac
     $ ../configure --without-iconv --without-ftp --without-http
   to generate config.h and include/libxml/xmlversion.h for Macs.
 - On Windows, run build/generate-win32-headers.bat to re-generate config.h and
   include/libxml/xmlversion.h for Windows builds.
 - Update this README to reflect the new version number.