Add a presubmit check to look for duplicate Valgrind/Heapchecker suppression name...

tools/heapcheck/PRESUBMIT.py

 # Copyright (c) 2010 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.
 
 """
 See http://dev.chromium.org/developers/how-tos/depottools/presubmit-scripts
 for more details on the presubmit API built into gcl.
 """
 
 def CheckChange(input_api, output_api):
   """Checks the memcheck suppressions files for bad data."""
+  suppressions = {}
   errors = []
   skip_next_line = False
   func_re = input_api.re.compile('[a-z_.]+\(.+\)$')
   for f, line_num, line in input_api.RightHandSideLines(lambda x:
       x.LocalPath().endswith('.txt')):
     line = line.lstrip()
     if line.startswith('#') or not line:
       continue
 
     if skip_next_line:
+      if suppressions.has_key(line):
+        errors.append('suppression with name "%s" at %s line %s has already '
+                      'been defined at line %s' % (line, f.LocalPath(),
+                                                   line_num,
+                                                   suppressions[line][1]))
+      else:
+        suppressions[line] = (f, line_num)
       skip_next_line = False
       continue
     if line == '{':
       skip_next_line = True
       continue
     if (line.startswith('fun:') or line.startswith('obj:') or
         line == 'Heapcheck:Leak' or line == '}' or
         line == '...'):
       continue
     if func_re.match(line):
       continue
     errors.append('"%s" is probably wrong: %s line %s' % (line, f.LocalPath(),
                                                           line_num))
   if errors:
     return [output_api.PresubmitError('\n'.join(errors))]
   return []
 
 def CheckChangeOnUpload(input_api, output_api):
   return CheckChange(input_api, output_api)
 
 def CheckChangeOnCommit(input_api, output_api):
   return CheckChange(input_api, output_api)