Remove GYP annotations from third_party GN files.

third_party/kasko/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("//build/buildflag_header.gni")
 import("//build/config/chrome_build.gni")
 import("//third_party/kasko/kasko.gni")
 
-# GYP version: target 'kasko_features' in third_party/kasko/kasko.gyp
 buildflag_header("kasko_features") {
   header = "kasko_features.h"
   flags = [ "ENABLE_KASKO=$enable_kasko" ]
 }
 
 if (enable_kasko) {
   assert(is_win, "Kasko only support Windows.")
   assert(target_cpu == "x86", "Kasko only support 32 bits.")
 
   # TODO(sebmarchand): Fix this once the Kasko dependency in SyzyAsan has been
   #     removed for the non-official builds.
   #assert(is_chrome_branded,
   #       "The Kasko client is only initialized in Chrome-branded builds.")
 
   config("kasko_config") {
     visibility = [ ":*" ]
     include_dirs = [ "//third_party/kasko/binaries/include" ]
     lib_dirs = [ "//third_party/kasko/binaries" ]
     libs = [ "kasko.dll.lib" ]
   }
 
-  # GYP version: target 'copy_kasko_dll' in third_party/kasko/kasko.gyp
   copy("copy_kasko_dll") {
     visibility = [ ":*" ]
     sources = [
       "//third_party/kasko/binaries/kasko.dll",
       "//third_party/kasko/binaries/kasko.dll.pdb",
     ]
     outputs = [
       "$root_out_dir/{{source_file_part}}",
     ]
   }
 
-  # GYP version: target 'kasko' in third_party/kasko/kasko.gyp
   group("kasko") {
     public_deps = [
       ":copy_kasko_dll",
       ":kasko_features",
     ]
     public_configs = [ ":kasko_config" ]
   }
 } else {
   group("kasko") {
     public_deps = [
       ":kasko_features",
     ]
   }
 }