New Zip::ZipFromMemory API.

third_party/zlib/google/zip.gyp

 # Copyright 2013 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.
 
 {
   'targets': [
     {
       'target_name': 'zip',
       'type': 'static_library',
       'dependencies': [
         '../zlib.gyp:minizip',
         '../../../base/base.gyp:base',
       ],
       'include_dirs': [
         '../../..',
       ],
       'sources': [
         'zip.cc',
         'zip.h',
         'zip_internal.cc',
         'zip_internal.h',
         'zip_reader.cc',
         'zip_reader.h',
+        'zip_writer.cc',
+        'zip_writer.h',
       ],
     },
   ],
 }