Update libwebp to 0.4.0

third_party/libwebp/utils/quant_levels_dec.h

 // Copyright 2013 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.
 // -----------------------------------------------------------------------------
 //
 // Alpha plane de-quantization utility
 //
 // Author:  Vikas Arora (vikasa@google.com)
 
 #ifndef WEBP_UTILS_QUANT_LEVELS_DEC_H_
 #define WEBP_UTILS_QUANT_LEVELS_DEC_H_
 
 #include "../webp/types.h"
 
-#if defined(__cplusplus) || defined(c_plusplus)
+#ifdef __cplusplus
 extern "C" {
 #endif
 
-// Apply post-processing to input 'data' of size 'width'x'height' assuming
-// that the source was quantized to a reduced number of levels.
+// Apply post-processing to input 'data' of size 'width'x'height' assuming that
+// the source was quantized to a reduced number of levels. The post-processing
+// will be applied to 'num_rows' rows of 'data' starting from 'row'.
 // Returns false in case of error (data is NULL, invalid parameters, ...).
-int DequantizeLevels(uint8_t* const data, int width, int height);
+int DequantizeLevels(uint8_t* const data, int width, int height,
+                     int row, int num_rows);
 
-#if defined(__cplusplus) || defined(c_plusplus)
+#ifdef __cplusplus
 }    // extern "C"
 #endif
 
 #endif  /* WEBP_UTILS_QUANT_LEVELS_DEC_H_ */