Allow multiple dart <script> tags in .sky files

sky/engine/core/BUILD.gn

 # Copyright 2014 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("//sky/engine/build/scripts/scripts.gni")
 import("//sky/engine/core/core.gni")
 
 visibility = [ "//sky/engine/*" ]
 
 rel_sky_core_gen_dir = rebase_path(sky_core_output_dir, root_build_dir)
@@ skipping 48 matching lines @@
     ":core_generated",
     ":libraries",
     ":prerequisites",
     "//sky/engine/platform",
     "//sky/engine/bindings",
     "//dart/runtime/bin:libdart_withcore",
   ]
 
   sources = sky_core_files
 
+  include_dirs = [
+    # Needed for dart_mirrors_api.h in dart_controller.cc
+    rebase_path("//dart/runtime"),
+  ]
+
   forward_dependent_configs_from = [ ":libraries" ]
 
   # core and core_generated are really the same thing.
   allow_circular_includes_from = [
     ":core_generated",
     "//sky/engine/bindings",
   ]
 }
 
 source_set("testing") {
@@ skipping 408 matching lines @@
     "$sky_core_output_dir/{{source_name_part}}.h",
   ]
   args = [
     "{{source}}",
     rel_sky_core_gen_dir,
     bison_exe,
   ]
 
   deps = make_core_generated_deps
 }