Reapply "Sharing of sources for corelib date implementation between VM

tools/create_sdk.py

 #!/usr/bin/env python
 #
 # Copyright (c) 2012, 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.
 #
 # A script which will be invoked from gyp to create an SDK.
 #
 # Usage: create_sdk.py sdk_directory
 #
@@ skipping 116 matching lines @@
   dealing with here which frees us from rewriting files. The long term
   plan is to align the layout of the repository and the SDK, at which
   point we should be able to simplify Main below and share the dart
   files between the various components to minimize SDK download size.
   '''
   copytree('lib', os.path.join(sdk_root, 'lib', 'dart2js', 'lib'),
            ignore=ignore_patterns('.svn'))
   copytree(os.path.join('corelib', 'src'),
            os.path.join(sdk_root, 'lib', 'dart2js', 'corelib', 'src'),
            ignore=ignore_patterns('.svn'))
-  copytree(os.path.join('corelib', 'unified'),
-           os.path.join(sdk_root, 'lib', 'dart2js', 'corelib', 'unified'),
-           ignore=ignore_patterns('.svn'))
   copytree(os.path.join('runtime', 'lib'),
            os.path.join(sdk_root, 'lib', 'dart2js', 'runtime', 'lib'),
            ignore=ignore_patterns('.svn'))
   copytree(os.path.join('runtime', 'bin'),
            os.path.join(sdk_root, 'lib', 'dart2js', 'runtime', 'bin'),
            ignore=ignore_patterns('.svn'))
   if utils.GuessOS() == 'win32':
     dart2js = os.path.join(sdk_root, 'bin', 'dart2js.bat')
     Copy(os.path.join(build_dir, 'dart2js.bat'), dart2js)
     ReplaceInFiles([dart2js],
@@ skipping 336 matching lines @@
   if revision is not None:
     with open(os.path.join(SDK_tmp, 'revision'), 'w') as f:
       f.write(revision + '\n')
       f.close()
 
   move(SDK_tmp, SDK)
   utils.Touch(os.path.join(SDK, 'create.stamp'))
 
 if __name__ == '__main__':
   sys.exit(Main(sys.argv))