Pass package-root option to dart2js in browser tests.

dart/tools/make_links.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.
 
 
 '''Tool for creating symlinks from SOURCES to TARGET.
 
 For each SOURCE in SOURCES create a link from SOURCE to TARGET.  If a
 SOURCE ends with .../lib, the lib suffix is ignored when determining
@@ skipping 21 matching lines @@
   if os.path.islink(target):
     print 'Removing %s' % target
     sys.stdout.flush()
     os.unlink(target)
 
   if os.path.isdir(target):
     print 'Removing %s' % target
     sys.stdout.flush()
     os.rmdir(target)
 
+  print 'Creating link from %s to %s' % (source, target)
+  sys.stdout.flush()
+
   if utils.GuessOS() == 'win32':
-    source = os.path.relpath(source)
     return subprocess.call(['mklink', '/j', target, source], shell=True)
   else:
-    source = os.path.relpath(source, start=target)
     return subprocess.call(['ln', '-s', source, target])
 
 
 def main(argv):
   target = os.path.relpath(argv[1])
   for source in argv[2:]:
     # Assume the source directory is named ".../TARGET_NAME/lib".
     (name, lib) = os.path.split(source)
     if lib != 'lib':
       name = source
     # Remove any addtional path components preceding TARGET_NAME.
     (path, name) = os.path.split(name)
+    if utils.GuessOS() == 'win32':
+      source = os.path.relpath(source)
+    else:
+      source = os.path.relpath(source, start=target)
     exit_code = make_link(source, os.path.join(target, name))
     if exit_code != 0:
       return exit_code
   return 0
 
 
 if __name__ == '__main__':
   sys.exit(main(sys.argv))