Tolerate the form 20xx-20xx for copyrights since it's used in a few headers.

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.
 
 """Top-level presubmit script for Chromium.
 
 See http://dev.chromium.org/developers/how-tos/depottools/presubmit-scripts
 for more details about the presubmit API built into gcl.
 """
 
 _EXCLUDED_PATHS = (
     r"breakpad[\\\/].*",
     r"skia[\\\/].*",
     r"v8[\\\/].*",
 )
 
 _TEXT_FILES = (
     r".*\.txt",
     r".*\.json",
 )
 
 _LICENSE_HEADER = (
-     r".*? Copyright \(c\) 20\d\d The Chromium Authors\. All rights reserved\."
-       "\n"
+     r".*? Copyright \(c\) 20[0-9\-]{2,7} The Chromium Authors\. All rights "
+       r"reserved\." "\n"
      r".*? Use of this source code is governed by a BSD-style license that can "
        "be\n"
      r".*? found in the LICENSE file\."
        "\n"
 )
 
 
 def _CommonChecks(input_api, output_api):
   results = []
   # What does this code do?
@@ skipping 169 matching lines @@
               'builds are pending.' % max_pendings,
           long_text='\n'.join(out))]
   except IOError:
     # Silently pass.
     pass
   return []
 
 
 def GetPreferredTrySlaves():
   return ['win', 'linux', 'mac']