Merge pull request #311 from abarth/more_sky_init

Run sky:init before creating a snapshot

engine/src/flutter/sky/packages/workbench/BUILD.gn

@@ -0,0 +1,16 @@
+# 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("init") {
+  stamp = "$target_gen_dir/sky_init.stamp"
+
+  script = "//sky/build/sky_init.py"
+  sources = [ "//sky/sdk/pubspec.yaml" ]
+  outputs = [ stamp ]
+
+  args = [
+    "--touch",
+    rebase_path(stamp, root_build_dir),
+  ]
+}