Fix gn check //sky/* to pass again.

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/bindings/scripts/scripts.gni")
 import("//sky/engine/build/scripts/scripts.gni")
 import("//sky/engine/core/core.gni")
 
 visibility = ["//sky/engine/*"]
 
@@ skipping 54 matching lines @@
     ":libraries",
     ":prerequisites",
     "//sky/engine/platform",
   ]
 
   sources = sky_core_files
 
   forward_dependent_configs_from = [
     ":libraries",
   ]
+
+  # core and core_generated are really the same thing.
+  allow_circular_includes_from = [ ":core_generated" ]
 }
 
 source_set("testing") {
   deps = [
     ":core",
     ":core_generated",
     ":prerequisites",
     "//sky/engine/platform",
     "//sky/engine/wtf",
   ]
@@ skipping 32 matching lines @@
 
   configs += [
     "..:inside_blink",
   ]
 
   deps = [
     ":make_core_generated",
     ":prerequisites",
     "//gin",
     "//skia",
+    "//sky/engine/bindings/core/v8:bindings_core_v8_generated",
+    "//sky/engine/platform",
+    "//sky/engine/wtf",
     "//third_party/iccjpeg",
     "//third_party/libpng",
     "//third_party/qcms",
-    "//sky/engine/bindings/core/v8:bindings_core_v8_generated",
-    "//sky/engine/wtf",
     "//url",
     "//v8",
   ]
 
   include_dirs = [
     "$root_build_dir",
   ]
 }
 
 # core_bindings_generated ------------------------------------------------------
@@ skipping 338 matching lines @@
     "$sky_core_output_dir/{{source_name_part}}.h",
   ]
   args = [
     "{{source}}",
     rel_sky_core_gen_dir,
     bison_exe,
   ]
 
   deps = make_core_generated_deps
 }