Add README file and parametrize result directory in layout test analzyer tool.

media/tools/layout_tests/trend_graph.py

 #!/usr/bin/python
 # Copyright (c) 2011 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 fileinput
 import os
 import sys
 
 
@@ skipping 27 matching lines @@
     There are two kinds of graphs to be updated (one is for numbers and the
     other is for passing rates).
 
     Args:
         datetime_string: a datetime string (e.g., '2008,1,1,13,45,00)'
         data_map: a dictionary containing 'whole', 'skip' , 'nonskip',
           'passingrate' as its keys and (number, tile, text) string tuples
           as values for graph annotation.
     """
     joined_str = ''
+    # For a date format in GViz, month is shifted (e.g., '2008,1,1' means

[dennis_jeffrey, 2011/09/01 00:29:13]

Maybe pick a slightly different example than "2008,1,1", since it's not clear
which of the two 1's is the month (though I suspect it's the first '1').  How
about this: '2008,2,1', which I think is 'March 1, 2008', right?

[imasaki1, 2011/09/01 03:08:23]

Done.

+    # Feb. 1st, 2008).
+    str_list = datetime_string.split(',')

[dennis_jeffrey, 2011/09/01 00:29:13]

Just to clarify: if we have 'Jan. 1, 2008', does that mean the inputted string
will be '2008,0,1'?

Or is it the reverse: the inputted string for 'Jan. 1, 2008' will be '2008,1,1',
and that's why we need to shift the month to instead be '2008,0,1'?

[imasaki1, 2011/09/01 03:08:23]

The input string for 'Jan. 1, 2008' is  '2008,0,1'.

[dennis_jeffrey, 2011/09/01 16:56:42]

Ok, if that is true, then won't line 51 below subtract 1 from the input '0' to
make it '-1' in the case of January ('2008,0,1' will become '2008,-1,1')?  That
seems weird to me.

[imasaki1, 2011/09/03 19:35:13]

Sorry I was not clear.

Input string ranges from (2008,1,1) to (2008,12,31) in the case of year 2008.
The output to gviz ranging from (2008,0,1) to (2008,11,31).

+    str_list[1] = str(int(str_list[1])-1) # month
+    datetime_string = ','.join(str_list)
     for key in ['whole', 'skip', 'nonskip']:
       joined_str += ','.join(data_map[key]) + ','
     new_line_for_numbers = '         [new Date(%s),%s],\n' % (datetime_string,
                                                               joined_str)
     new_line_for_numbers += '         %s\n' % (
         LINE_INSERT_POINT_FOR_NUMBERS)
     self._ReplaceLine(LINE_INSERT_POINT_FOR_NUMBERS, new_line_for_numbers)
 
     joined_str = '%s,%s,%s' % (
         data_map['passingrate'][0], data_map['nonskip'][1],
@@ skipping 11 matching lines @@
     Args:
         search_exp: search expression to find a line to be replaced.
         replace_line: the new line.
     """
     replaced = False
     for line in fileinput.input(self._location, inplace=1):
       if search_exp in line:
         replaced = True
         line = replace_line
       sys.stdout.write(line)