Update libwebp to 0.4.0

third_party/libwebp/libwebp.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.
 
 {
   'targets': [
     {
       'target_name': 'libwebp_dec',
       'type': 'static_library',
       'dependencies' : [
@@ skipping 100 matching lines @@
         'enc/tree.c',
         'enc/vp8l.c',
         'enc/webpenc.c',
       ],
     },
     {
       'target_name': 'libwebp_utils',
       'type': 'static_library',
       'include_dirs': ['.'],
       'sources': [
+        'utils/alpha_processing.c',
         'utils/bit_reader.c',
         'utils/bit_writer.c',
         'utils/color_cache.c',
         'utils/filters.c',
         'utils/huffman.c',
         'utils/huffman_encode.c',
         'utils/quant_levels.c',
         'utils/quant_levels_dec.c',
+        'utils/random.c',
         'utils/rescaler.c',
         'utils/thread.c',
         'utils/utils.c',
       ],
     },
     {
       'target_name': 'libwebp',
       'type': 'none',
       'dependencies' : [
         'libwebp_dec',
         'libwebp_demux',
         'libwebp_dsp',
         'libwebp_dsp_neon',
         'libwebp_enc',
         'libwebp_utils',
       ],
       'direct_dependent_settings': {
         'include_dirs': ['.'],
       },
       'conditions': [
         ['OS!="win"', {'product_name': 'webp'}],
       ],
     },
   ],
 }