Initial import.

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diff --git a/chromium/skia/ext/recursive_gaussian_convolution.h b/chromium/skia/ext/recursive_gaussian_convolution.h
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+++ b/chromium/skia/ext/recursive_gaussian_convolution.h
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+// Copyright (c) 2013 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.
+
+#ifndef SKIA_EXT_RECURSIVE_GAUSSIAN_CONVOLUTION_H_
+#define SKIA_EXT_RECURSIVE_GAUSSIAN_CONVOLUTION_H_
+
+#include "skia/ext/convolver.h"
+#include "third_party/skia/include/core/SkSize.h"
+#include "third_party/skia/include/core/SkTypes.h"
+
+namespace skia {
+
+// RecursiveFilter, paired with SingleChannelRecursiveGaussianX and
+// SingleChannelRecursiveGaussianY routines below implement recursive filters as
+// described in 'Recursive implementation of the Gaussian filter' (Young, Vliet)
+// (1995). Single-letter variable names mirror exactly the usage in the paper to
+// ease reading and analysis.
+class RecursiveFilter {
+ public:
+  enum Order {
+    FUNCTION,
+    FIRST_DERIVATIVE,
+    SECOND_DERIVATIVE
+  };
+
+  static float qFromSigma(float sigma);
+  static void computeCoefficients(float q, float b[4]);
+  SK_API RecursiveFilter(float sigma, Order order);
+
+  Order order() const { return order_; }
+  const float* b() const { return b_; }
+
+ private:
+  Order order_;
+  float q_;
+  float b_[4];
+};
+
+// Applies a gaussian recursive filter given as |filter| to a single channel at
+// |input_channel_index| to image given in |source_data| along X axis.
+// The output is placed into |output| into channel |output_channel_index|.
+SK_API unsigned char SingleChannelRecursiveGaussianX(
+    const unsigned char* source_data,
+    int source_byte_row_stride,
+    int input_channel_index,
+    int input_channel_count,
+    const RecursiveFilter& filter,
+    const SkISize& image_size,
+    unsigned char* output,
+    int output_byte_row_stride,
+    int output_channel_index,
+    int output_channel_count,
+    bool absolute_values);
+
+// Applies a gaussian recursive filter along Y axis.
+SK_API unsigned char  SingleChannelRecursiveGaussianY(
+    const unsigned char* source_data,
+    int source_byte_row_stride,
+    int input_channel_index,
+    int input_channel_count,
+    const RecursiveFilter& filter,
+    const SkISize& image_size,
+    unsigned char* output,
+    int output_byte_row_stride,
+    int output_channel_index,
+    int output_channel_count,
+    bool absolute_values);
+}  // namespace skia
+
+#endif  // SKIA_EXT_RECURSIVE_GAUSSIAN_CONVOLUTION_H_