Remove som GYP annotations, remove unused manifest.

chromecast/app/BUILD.gn

 # 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.
 
 import("//testing/test.gni")
 import("//tools/grit/grit_rule.gni")
 
 source_set("app") {
   sources = [
     "cast_main_delegate.cc",
@@ skipping 56 matching lines @@
     "//base",
     "//base/test:run_all_unittests",
     "//base/test:test_support",
     "//chromecast/base:test_support",
     "//chromecast/crash",
     "//chromecast/crash:test_support",
     "//testing/gtest",
   ]
 }
 
-# GYP target: chromecast.gyp:cast_shell_resources
 grit("resources") {
   source = "//chromecast/app/resources/shell_resources.grd"
 
   resource_ids = "//chromecast/app/resources/resource_ids"
 
   outputs = [
     "grit/shell_resources.h",
     "shell_resources.pak",
   ]
 }
 
-# GYP target: chromecast_locales.gyp:chromecast_settings
 grit("chromecast_settings") {
   source = "//chromecast/app/resources/chromecast_settings.grd"
   resource_ids = "//chromecast/app/resources/resource_ids"
   output_dir = "$root_gen_dir/chromecast_strings"
 
   outputs = [
     "grit/chromecast_settings.h",
     "chromecast_settings_am.pak",
     "chromecast_settings_ar.pak",
     "chromecast_settings_bg.pak",
@@ skipping 43 matching lines @@
     "chromecast_settings_ta.pak",
     "chromecast_settings_te.pak",
     "chromecast_settings_th.pak",
     "chromecast_settings_tr.pak",
     "chromecast_settings_uk.pak",
     "chromecast_settings_vi.pak",
     "chromecast_settings_zh-CN.pak",
     "chromecast_settings_zh-TW.pak",
   ]
 }