Update Linux size expectations.

tools/perf_expectations/make_expectations.py

 #!/usr/bin/env 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.
 
+# For instructions see:
+# http://www.chromium.org/developers/tree-sheriffs/perf-sheriffs
 
 import hashlib
 import math
 import optparse
 import os
 import re
 import subprocess
 import sys
 import time
 import urllib2
@@ skipping 323 matching lines @@
     print 'done'
   else:
     if options.verbose:
       print ''
     print 'No changes.'
   return 0
 
 
 if __name__ == '__main__':
   sys.exit(Main(sys.argv))