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

printing/printing.gyp

 # Copyright (c) 2012 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.
 
 {
   'variables': {
     'chromium_code': 1,
   },
   'targets': [
     {
@@ skipping 26 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 252 matching lines @@
           },
           'dependencies': [
             '../base/base.gyp:base_java',
           ],
           'includes': [ '../build/java.gypi'  ],
         }
       ]
     }],
   ]
 }