Use AutofillProfileComparator in place of ad-hoc merge logic.

components/test/data/autofill/merge/tools/autofill_merge_common.py

 # Copyright 2013 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.
 
 
 class UnknownColumnNameException(Exception):
   """Exception type raised when encountering an unknown column name."""
   def __init__(self, column_name):
     self.column_name = column_name
   def __str__(self):
     return repr(self.column_name)
 
 
 def SerializeProfiles(profiles):
   """Returns a serialized string for the given |profiles|.
 
   |profiles| should be a list of (field_type, value) string pairs.
 
   """
 
   lines = []
   for profile in profiles:
     # Include a fixed string to separate profiles.
     lines.append("---")
     for (field_type, value) in profile:
       if field_type == "ignored":
         continue;
 
-      lines.append("%s: %s" % (field_type, value))
+      lines.append("%s:%s%s" % (field_type, (' ' if value else ''), value))
 
   return '\n'.join(lines)
 
 
 def ColumnNameToFieldType(column_name):
   """Converts the given |column_name| to the corresponding AutofillField type.
 
   |column_name| should be a string drawn from the column names of the
   autofill_profiles table in the Chromium "Web Data" database.
 
@@ skipping 30 matching lines @@
   elif column_name == "zipcode":
     field_type = "ADDRESS_HOME_ZIP"
   elif column_name == "country_code":
     field_type = "ADDRESS_HOME_COUNTRY"
   elif column_name == "phone":
     field_type = "PHONE_HOME_WHOLE_NUMBER"
   else:
     raise UnknownColumnNameException(column_name)
 
   return field_type