Fixing gn manifests for many executables

chrome/browser/nacl_host/test/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/config/features.gni")
 
 if (enable_nacl && (is_linux || is_win)) {
   executable("mock_nacl_gdb") {
     sources = [
       "mock_nacl_gdb.cc",
     ]
     deps = [
       "//base",
+
+      # Default manifest on Windows (a no-op elsewhere).
+      "//build/win:default_exe_manifest",
     ]
   }
 }