Roll libwebp to v0.4.2 (latest stable) to fix annoying build warning.

gyp/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.
 
 {
   'variables': {
     'skia_warnings_as_errors': 0,
     'conditions':[
       ['skia_android_framework == 1', {
         'use_system_libwebp': 1,
@@ skipping 10 matching lines @@
           'type': 'static_library',
           'include_dirs': [
               '../third_party/externals/libwebp',
           ],
           'sources': [
             '../third_party/externals/libwebp/src/dec/alpha.c',
             '../third_party/externals/libwebp/src/dec/buffer.c',
             '../third_party/externals/libwebp/src/dec/frame.c',
             '../third_party/externals/libwebp/src/dec/idec.c',
             '../third_party/externals/libwebp/src/dec/io.c',
-            '../third_party/externals/libwebp/src/dec/layer.c',
             '../third_party/externals/libwebp/src/dec/quant.c',
             '../third_party/externals/libwebp/src/dec/tree.c',
             '../third_party/externals/libwebp/src/dec/vp8.c',
             '../third_party/externals/libwebp/src/dec/vp8l.c',
             '../third_party/externals/libwebp/src/dec/webp.c',
           ],
           'cflags': [ '-w' ],
         },
         {
           'target_name': 'libwebp_demux',
           'type': 'static_library',
           'include_dirs': [
               '../third_party/externals/libwebp',
           ],
           'sources': [
             '../third_party/externals/libwebp/src/demux/demux.c',
           ],
           'cflags': [ '-w' ],
         },
         {
           'target_name': 'libwebp_dsp',
           'type': 'static_library',
           'include_dirs': [
               '../third_party/externals/libwebp',
           ],
           'sources': [
+            '../third_party/externals/libwebp/src/dsp/alpha_processing.c',
+            '../third_party/externals/libwebp/src/dsp/alpha_processing_sse2.c',
             '../third_party/externals/libwebp/src/dsp/cpu.c',
             '../third_party/externals/libwebp/src/dsp/dec.c',
+            '../third_party/externals/libwebp/src/dsp/dec_clip_tables.c',
             '../third_party/externals/libwebp/src/dsp/dec_sse2.c',
             '../third_party/externals/libwebp/src/dsp/enc.c',
             '../third_party/externals/libwebp/src/dsp/enc_sse2.c',
             '../third_party/externals/libwebp/src/dsp/lossless.c',
+            '../third_party/externals/libwebp/src/dsp/lossless_sse2.c',
             '../third_party/externals/libwebp/src/dsp/upsampling.c',
             '../third_party/externals/libwebp/src/dsp/upsampling_sse2.c',
             '../third_party/externals/libwebp/src/dsp/yuv.c',
+            '../third_party/externals/libwebp/src/dsp/yuv_sse2.c',
           ],
           'cflags': [ '-w' ],
           'conditions': [
             ['skia_os == "android"', {
               'dependencies' : [
                 'android_deps.gyp:cpu_features',
               ],
             }],
           ],
         },
         {
           'target_name': 'libwebp_dsp_neon',
           'conditions': [
             ['arm_version >= 7', {
               'type': 'static_library',
               'include_dirs': [
                   '../third_party/externals/libwebp',
               ],
               'sources': [
                 '../third_party/externals/libwebp/src/dsp/dec_neon.c',
                 '../third_party/externals/libwebp/src/dsp/enc_neon.c',
+                '../third_party/externals/libwebp/src/dsp/lossless_neon.c',
                 '../third_party/externals/libwebp/src/dsp/upsampling_neon.c',
               ],
               # behavior similar dsp_neon.c.neon in an Android.mk
               'cflags!': [
                 '-mfpu=vfpv3-d16',
               ],
               'cflags': [ '-mfpu=neon', '-w' ],
             },{  # !(arm_version >= 7)
               'type': 'none',
             }],
           ],
         },
         {
           'target_name': 'libwebp_enc',
           'type': 'static_library',
           'include_dirs': [
               '../third_party/externals/libwebp',
           ],
           'sources': [
             '../third_party/externals/libwebp/src/enc/alpha.c',
             '../third_party/externals/libwebp/src/enc/analysis.c',
             '../third_party/externals/libwebp/src/enc/backward_references.c',
             '../third_party/externals/libwebp/src/enc/config.c',
             '../third_party/externals/libwebp/src/enc/cost.c',
             '../third_party/externals/libwebp/src/enc/filter.c',
             '../third_party/externals/libwebp/src/enc/frame.c',
             '../third_party/externals/libwebp/src/enc/histogram.c',
             '../third_party/externals/libwebp/src/enc/iterator.c',
-            '../third_party/externals/libwebp/src/enc/layer.c',
             '../third_party/externals/libwebp/src/enc/picture.c',
+            '../third_party/externals/libwebp/src/enc/picture_csp.c',
+            '../third_party/externals/libwebp/src/enc/picture_psnr.c',
+            '../third_party/externals/libwebp/src/enc/picture_rescale.c',
+            '../third_party/externals/libwebp/src/enc/picture_tools.c',
             '../third_party/externals/libwebp/src/enc/quant.c',
             '../third_party/externals/libwebp/src/enc/syntax.c',
             '../third_party/externals/libwebp/src/enc/token.c',
             '../third_party/externals/libwebp/src/enc/tree.c',
             '../third_party/externals/libwebp/src/enc/vp8l.c',
             '../third_party/externals/libwebp/src/enc/webpenc.c',
           ],
           'cflags': [ '-w' ],
         },
         {
           'target_name': 'libwebp_utils',
           'type': 'static_library',
           'include_dirs': [
               '../third_party/externals/libwebp',
           ],
           'sources': [
             '../third_party/externals/libwebp/src/utils/bit_reader.c',
             '../third_party/externals/libwebp/src/utils/bit_writer.c',
             '../third_party/externals/libwebp/src/utils/color_cache.c',
             '../third_party/externals/libwebp/src/utils/filters.c',
             '../third_party/externals/libwebp/src/utils/huffman.c',
             '../third_party/externals/libwebp/src/utils/huffman_encode.c',
             '../third_party/externals/libwebp/src/utils/quant_levels.c',
             '../third_party/externals/libwebp/src/utils/quant_levels_dec.c',
+            '../third_party/externals/libwebp/src/utils/random.c',
             '../third_party/externals/libwebp/src/utils/rescaler.c',
             '../third_party/externals/libwebp/src/utils/thread.c',
             '../third_party/externals/libwebp/src/utils/utils.c',
           ],
           'cflags': [ '-w' ],
         },
         {
           'target_name': 'libwebp',
           'type': 'none',
           'dependencies' : [
@@ skipping 46 matching lines @@
                   ],
                 },
               },
             ],
           ],
         }
       ],
     }],
   ],
 }