Build skia as a dll in windows multi-dll build.

ppapi/ppapi_shared_proxy.gypi

 # Copyright (c) 2010 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': 'ppapi_shared_impl',
       'type': 'static_library',
       'dependencies': [
         'ppapi_c',
         '../base/base.gyp:base',
+        '../skia/skia.gyp:skia',
         '../third_party/icu/icu.gyp:icuuc',
       ],
       'include_dirs': [
         '..',
       ],
       'sources': [
         'shared_impl/audio_impl.cc',
         'shared_impl/audio_impl.h',
         'shared_impl/char_set_impl.cc',
         'shared_impl/char_set_impl.h',
@@ skipping 128 matching lines @@
         ['OS=="win"', {
         }],
         ['OS=="linux"', {
         }],
         ['OS=="mac"', {
         }]
       ],
     },
   ],
 }