Use the upstream version of libwebp, v0.4.3.

third_party/libwebp/utils/filters.h

Index: third_party/libwebp/utils/filters.h
diff --git a/third_party/libwebp/utils/filters.h b/third_party/libwebp/utils/filters.h
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+// 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.
+// -----------------------------------------------------------------------------
+//
+// Spatial prediction using various filters
+//
+// Author: Urvang (urvang@google.com)
+
+#ifndef WEBP_UTILS_FILTERS_H_
+#define WEBP_UTILS_FILTERS_H_
+
+#include "../webp/types.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+// Filters.
+typedef enum {
+  WEBP_FILTER_NONE = 0,
+  WEBP_FILTER_HORIZONTAL,
+  WEBP_FILTER_VERTICAL,
+  WEBP_FILTER_GRADIENT,
+  WEBP_FILTER_LAST = WEBP_FILTER_GRADIENT + 1,  // end marker
+  WEBP_FILTER_BEST,
+  WEBP_FILTER_FAST
+} WEBP_FILTER_TYPE;
+
+typedef void (*WebPFilterFunc)(const uint8_t* in, int width, int height,
+                               int stride, uint8_t* out);
+typedef void (*WebPUnfilterFunc)(int width, int height, int stride,
+                                 int row, int num_rows, uint8_t* data);
+
+// Filter the given data using the given predictor.
+// 'in' corresponds to a 2-dimensional pixel array of size (stride * height)
+// in raster order.
+// 'stride' is number of bytes per scan line (with possible padding).
+// 'out' should be pre-allocated.
+extern const WebPFilterFunc WebPFilters[WEBP_FILTER_LAST];
+
+// In-place reconstruct the original data from the given filtered data.
+// The reconstruction will be done for 'num_rows' rows starting from 'row'
+// (assuming rows upto 'row - 1' are already reconstructed).
+extern const WebPUnfilterFunc WebPUnfilters[WEBP_FILTER_LAST];
+
+// Fast estimate of a potentially good filter.
+WEBP_FILTER_TYPE EstimateBestFilter(const uint8_t* data,
+                                    int width, int height, int stride);
+
+#ifdef __cplusplus
+}    // extern "C"
+#endif
+
+#endif  /* WEBP_UTILS_FILTERS_H_ */