Add support for ignoring the svn revision when getting the version, use this for gn build

tools/make_version.py

 # Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 # for details. All rights reserved. Use of this source code is governed by a
 # BSD-style license that can be found in the LICENSE file.
 #
 # This python script creates a version string in a C++ file.
 
 import hashlib
 import os
 import sys
 import time
@@ skipping 17 matching lines @@
   # Source files.
   'dart.cc',
   'dart_api_impl.cc',
   'object.cc',
   'raw_object.cc',
   'raw_object_snapshot.cc',
   'snapshot.cc',
   'symbols.cc',
 ]
 
-def makeVersionString(quiet):
-  version_string = utils.GetVersion()
+def makeVersionString(quiet, no_svn):
+  version_string = utils.GetSemanticSDKVersion(ignore_svn_revision=no_svn)
   if not quiet:
     debugLog("Returning version string: %s " % version_string)
   return version_string
 
 
 def makeSnapshotHashString():
   vmhash = hashlib.md5()
   for vmfilename in VM_SNAPSHOT_FILES:
     vmfilepath = os.path.join(utils.DART_DIR, 'runtime', 'vm', vmfilename)
     with open(vmfilepath) as vmfile:
       vmhash.update(vmfile.read())
   return vmhash.hexdigest()
 
 
-def makeFile(quiet, output_file, input_file):
+def makeFile(quiet, output_file, input_file, ignore_svn_revision):
   version_cc_text = open(input_file).read()
-  version_string = makeVersionString(quiet)
+  version_string = makeVersionString(quiet, ignore_svn_revision)
   version_cc_text = version_cc_text.replace("{{VERSION_STR}}",
                                             version_string)
   version_time = time.ctime(time.time())
   version_cc_text = version_cc_text.replace("{{BUILD_TIME}}",
                                             version_time)
   snapshot_hash = makeSnapshotHashString()
   version_cc_text = version_cc_text.replace("{{SNAPSHOT_HASH}}",
                                             snapshot_hash)
   open(output_file, 'w').write(version_cc_text)
   return True
 
 
 def main(args):
   try:
     # Parse input.
     parser = OptionParser()
     parser.add_option("-q", "--quiet",
                       action="store_true", default=False,
                       help="disable console output")
+    parser.add_option("--ignore_svn_revision",
+                      action="store_true", default=False,
+                      help="Don't try to determine svn revision")
     parser.add_option("--output",
                       action="store", type="string",
                       help="output file name")
     parser.add_option("--input",
                       action="store", type="string",
                       help="input template file")
 
     (options, args) = parser.parse_args()
     if not options.output:
       sys.stderr.write('--output not specified\n')
       return -1
     if not len(options.input):
       sys.stderr.write('--input not specified\n')
       return -1
 
     files = []
     for arg in args:
       files.append(arg)
 
-    if not makeFile(options.quiet, options.output, options.input):
+    if not makeFile(options.quiet, options.output, options.input,
+                    options.ignore_svn_revision):
       return -1
 
     return 0
   except Exception, inst:
     sys.stderr.write('make_version.py exception\n')
     sys.stderr.write(str(inst))
     sys.stderr.write('\n')
     return -1
 
 if __name__ == '__main__':
   exit_code = main(sys.argv)
   sys.exit(exit_code)