Improve GN header checker, make //ui pass.

ui/keyboard/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("//mojo/public/tools/bindings/mojom.gni")
 import("//tools/grit/grit_rule.gni")
 
 component("keyboard") {
   sources = [
     "keyboard.cc",
@@ skipping 65 matching lines @@
   ]
 
   deps = [
     ":keyboard_mojom_bindings",
   ]
 }
 
 copy("resources") {
   sources = [ "$target_gen_dir/keyboard_resources.pak" ]
   outputs = [ "$root_out_dir/keyboard_resources.pak" ]
-  deps = [ ":resources_grit" ]
-  forward_dependent_configs_from = deps
+  public_deps = [ ":resources_grit" ]
 }
 
 test("keyboard_unittests") {
   sources = [
     "test/run_all_unittests.cc",
     "keyboard_controller_unittest.cc",
   ]
 
   deps = [
     ":keyboard",
     "//base",
     "//base/allocator",
     "//base/test:test_support",
     "//content",
     "//skia",
     "//testing/gtest",
-    "//ui/aura",
     "//ui/aura:test_support",
-    "//ui/base",
-    "//ui/compositor",
+    "//ui/base:test_support",
     "//ui/compositor:test_support",
+    "//ui/events:test_support",
     "//ui/gfx",
     "//ui/gfx/geometry",
     "//ui/gl",
     "//ui/resources:ui_test_pak",
     "//ui/wm",
     "//url",
   ]
 }