Removed NativeMetafile and PreviewMetafile typedef as it's always PdfMetafileSkia.

printing/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("//build/config/features.gni")
 import("//build/config/ui.gni")
 if (is_mac) {
   import("//build/config/mac/mac_sdk.gni")
 }
 if (is_android) {
@@ skipping 11 matching lines @@
     "backend/printing_info_win.h",
     "emf_win.cc",
     "emf_win.h",
     "image.cc",
     "image.h",
     "image_android.cc",
     "image_linux.cc",
     "image_mac.cc",
     "image_win.cc",
     "metafile.h",
-    "metafile_impl.h",
     "metafile_skia_wrapper.cc",
     "metafile_skia_wrapper.h",
     "page_number.cc",
     "page_number.h",
     "page_range.cc",
     "page_range.h",
     "page_setup.cc",
     "page_setup.h",
     "page_size_margins.h",
     "pdf_metafile_cg_mac.cc",
@@ skipping 204 matching lines @@
   #  'type': 'none',
   #  'variables': {
   #    'java_in_dir': '../printing/android/java',
   #  },
   #  'dependencies': [
   #    '../base/base.gyp:base_java',
   #  ],
   #  'includes': [ '../build/java.gypi'  ],
   #}
 }