libwebp: update to v0.5.1

third_party/libwebp/enc/picture.c

 // Copyright 2011 Google Inc. All Rights Reserved.
 //
 // Use of this source code is governed by a BSD-style license
 // that can be found in the COPYING file in the root of the source
 // tree. An additional intellectual property rights grant can be found
 // in the file PATENTS. All contributing project authors may
 // be found in the AUTHORS file in the root of the source tree.
 // -----------------------------------------------------------------------------
 //
 // WebPPicture class basis
@@ skipping 219 matching lines @@
 typedef int (*Importer)(WebPPicture* const, const uint8_t* const, int);
 
 static size_t Encode(const uint8_t* rgba, int width, int height, int stride,
                      Importer import, float quality_factor, int lossless,
                      uint8_t** output) {
   WebPPicture pic;
   WebPConfig config;
   WebPMemoryWriter wrt;
   int ok;
 
+  if (output == NULL) return 0;
+
   if (!WebPConfigPreset(&config, WEBP_PRESET_DEFAULT, quality_factor) ||
       !WebPPictureInit(&pic)) {
     return 0;  // shouldn't happen, except if system installation is broken
   }
 
   config.lossless = !!lossless;
   pic.use_argb = !!lossless;
   pic.width = width;
   pic.height = height;
   pic.writer = WebPMemoryWrite;
@@ skipping 31 matching lines @@
 }
 
 LOSSLESS_ENCODE_FUNC(WebPEncodeLosslessRGB, WebPPictureImportRGB)
 LOSSLESS_ENCODE_FUNC(WebPEncodeLosslessBGR, WebPPictureImportBGR)
 LOSSLESS_ENCODE_FUNC(WebPEncodeLosslessRGBA, WebPPictureImportRGBA)
 LOSSLESS_ENCODE_FUNC(WebPEncodeLosslessBGRA, WebPPictureImportBGRA)
 
 #undef LOSSLESS_ENCODE_FUNC
 
 //------------------------------------------------------------------------------