Unhook packages/material_design_icons from the build

We don't have any use for this symlink in the out directory anymore.
This patch lets us remove our fork of build/symlink.py.

sky/build/symlink.py

-#!/usr/bin/env python
-# Copyright (c) 2013 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.
-
-import errno
-import optparse
-import os.path
-import shutil
-import sys
-
-
-def main(argv):
-    parser = optparse.OptionParser()
-    parser.add_option('--touch')
-
-    options, args = parser.parse_args(argv[1:])
-    if len(args) != 2:
-        parser.error('Two arguments required.')
-
-    source = os.path.abspath(args[0])
-    target = os.path.abspath(args[1])
-    try:
-        os.symlink(source, target)
-    except OSError, e:
-        if e.errno == errno.EEXIST:
-            os.remove(target)
-            os.symlink(source, target)
-
-    if options.touch:
-        with open(os.path.abspath(options.touch), 'w') as f:
-            pass
-
-
-if __name__ == '__main__':
-  sys.exit(main(sys.argv))

sky/packages/BUILD.gn

@@ -8,6 +8,5 @@ group("packages") {
   deps = [
     "//sky/packages/sky_engine",
     "//sky/packages/sky_services",
-    "//sky/packages/material_design_icons",
   ]
 }

sky/packages/material_design_icons/BUILD.gn

-# Copyright 2015 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.
-
-action("material_design_icons") {
-  script = "//sky/build/symlink.py"
-
-  stamp_file = "$target_gen_dir/symlink.stamp"
-
-  sources = [ "lib/.version.sha1" ]
-  outputs = [ stamp_file ]
-
-  args = [
-    rebase_path("lib", root_build_dir),
-    rebase_path("$root_gen_dir/dart-pkg/packages/material_design_icons", root_build_dir),
-    "--touch",
-    rebase_path(stamp_file, root_build_dir)
-  ]
-}