Rationalize Dart mojo and sky package structure

sky/sdk/packages/sky/lib/download_material_design_icons

Index: sky/sdk/packages/sky/lib/download_material_design_icons
diff --git a/sky/sdk/packages/sky/lib/download_material_design_icons b/sky/sdk/packages/sky/lib/download_material_design_icons
deleted file mode 100755
index 6087c48fb89e9c15ebe598d9f5393fd259ed7517..0000000000000000000000000000000000000000
--- a/sky/sdk/packages/sky/lib/download_material_design_icons
+++ /dev/null
@@ -1,29 +0,0 @@
-#!/usr/bin/env python
-# Copyright (c) 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.
-
-import os
-import subprocess
-import urllib2
-
-sky_lib_dir = os.path.dirname(os.path.abspath(__file__))
-assets_dir = os.path.join(sky_lib_dir, 'assets')
-sha1_path = os.path.join(assets_dir, 'material-design-icons.sha1')
-
-with open(sha1_path, 'r') as f:
-    sha1 = f.read()
-
-tgz_path = os.path.join(assets_dir, 'material-design-icons.tgz')
-url = 'https://storage.googleapis.com/mojo/material-design-icons/%s' % sha1
-response = urllib2.urlopen(url)
-
-with open(tgz_path, 'wb') as f:
-    f.write(response.read())
-
-output_path = os.path.join(assets_dir, tgz_path)
-subprocess.call([
-    'tar', '-xzf', output_path, '-C', assets_dir
-])
-
-os.unlink(tgz_path)