Always install xfonts-mathml package if it is available.

build/experimental/install-build-deps.py

 #!/usr/bin/env python
 # Copyright 2015 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import argparse
 import operator
 import os
 import platform
 import re
@@ skipping 343 matching lines @@
   if package_exists('libbrlapi0.6'):
     _packages_dev += ('libbrlapi0.6',)
   else:
     _packages_dev += ('libbrlapi0.5',)
 
   if package_exists('apache2-bin'):
     _packages_dev += ('apache2-bin',)
   else:
     _packages_dev += ('apache2.2-bin',)
 
-  if package_exists('fonts-stix'):
-    _packages_dev += ('fonts-stix',)
-  else:
+  if package_exists('xfonts-mathml'):
     _packages_dev += ('xfonts-mathml',)
 
   # Some packages are only needed if the distribution actually supports
   # installing them.
   if package_exists('appmenu-gtk'):
     _packages_lib += ('appmenu-gtk',)
 
   _packages_dev += _packages_chromeos_dev
   _packages_lib += _packages_chromeos_lib
   _packages_nacl += _packages_naclports
@@ skipping 50 matching lines @@
   packages = sorted(set(packages), key=packages_key)
 
   if args.quick_check:
     return quick_check(packages)
 
   return 0
 
 
 if __name__ == '__main__':
   sys.exit(main(sys.argv[1:]))