Revert of mojo: fix python unittests.

mojo/public/python/mojo/bindings/descriptor.py

 # Copyright 2014 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.
 
 """
 The descriptors used to define generated elements of the mojo python bindings.
 """
 
 import array
 import itertools
@@ skipping 187 matching lines @@
 
   def SerializePointer(self, value, data_offset, data, handle_offset):
     string_array = array.array('b')
     string_array.fromstring(value.encode('utf8'))
     return self._array_type.SerializeArray(
         string_array, data_offset, data, handle_offset)
 
   def DeserializePointer(self, size, nb_elements, data, handles):
     string_array = self._array_type.DeserializeArray(
         size, nb_elements, data, handles)
-    return unicode(string_array.tostring(), 'utf8')
+    return unicode(buffer(string_array), 'utf8')
 
 
 class HandleType(SerializableType):
   """Type object for handles."""
 
   def __init__(self, nullable=False):
     SerializableType.__init__(self, 'i')
     self.nullable = nullable
 
   def Convert(self, value):
@@ skipping 326 matching lines @@
 
 
 def _ConvertByteToBooleans(value, min_size=0):
   "Unpack an integer into a list of booleans."""
   res = []
   while value:
     res.append(bool(value&1))
     value = value / 2
   res.extend([False] * (min_size - len(res)))
   return res