Update libwebp to 0.4.0

third_party/libwebp/utils/alpha_processing.h

Index: third_party/libwebp/utils/alpha_processing.h
diff --git a/third_party/libwebp/utils/alpha_processing.h b/third_party/libwebp/utils/alpha_processing.h
new file mode 100644
index 0000000000000000000000000000000000000000..80e1ae45ddef34496c4e41641b3eaaec5c1e8337
--- /dev/null
+++ b/third_party/libwebp/utils/alpha_processing.h
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+// 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.
+// -----------------------------------------------------------------------------
+//
+// Utilities for processing transparent channel.
+//
+// Author: Skal (pascal.massimino@gmail.com)
+
+#ifndef WEBP_UTILS_ALPHA_PROCESSING_H_
+#define WEBP_UTILS_ALPHA_PROCESSING_H_
+
+#include "../webp/types.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+// Pre-Multiply operation transforms x into x * A / 255  (where x=Y,R,G or B).
+// Un-Multiply operation transforms x into x * 255 / A.
+
+// Pre-Multiply or Un-Multiply (if 'inverse' is true) argb values in a row.
+void WebPMultARGBRow(uint32_t* const ptr, int width, int inverse);
+
+// Same a WebPMultARGBRow(), but for several rows.
+void WebPMultARGBRows(uint8_t* ptr, int stride, int width, int num_rows,
+                      int inverse);
+
+// Same for a row of single values, with side alpha values.
+void WebPMultRow(uint8_t* const ptr, const uint8_t* const alpha,
+                 int width, int inverse);
+
+// Same a WebPMultRow(), but for several 'num_rows' rows.
+void WebPMultRows(uint8_t* ptr, int stride,
+                  const uint8_t* alpha, int alpha_stride,
+                  int width, int num_rows, int inverse);
+
+#ifdef __cplusplus
+}    // extern "C"
+#endif
+
+#endif    // WEBP_UTILS_ALPHA_PROCESSING_H_