Move image_diff code into testing/image_diff/

It is not actually a sample program to demonstrate how to use PDFium
APIs. It is more of a test utility program.

Remove header include dependency from samples/ to core/, to set a good
example.

Change-Id: Idd5d567c82314bcf0e4a7bec8a3210e7d57226ee
Reviewed-on: https://pdfium-review.googlesource.com/6871
Reviewed-by: dsinclair <dsinclair@chromium.org>
Commit-Queue: Lei Zhang <thestig@chromium.org>

1 files changed, 38 insertions, 0 deletions

diff --git a/testing/image_diff/image_diff_png.h b/testing/image_diff/image_diff_png.h
new file mode 100644
index 0000000000..4d87aa1cc0
--- /dev/null
+++ b/testing/image_diff/image_diff_png.h
@@ -0,0 +1,38 @@
+// Copyright 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 TESTING_IMAGE_DIFF_IMAGE_DIFF_PNG_H_
+#define TESTING_IMAGE_DIFF_IMAGE_DIFF_PNG_H_
+
+#include <stdlib.h>  // for size_t.
+
+#include <vector>
+
+namespace image_diff_png {
+
+// Decode a PNG into an RGBA pixel array.
+bool DecodePNG(const unsigned char* input,
+               size_t input_size,
+               std::vector<unsigned char>* output,
+               int* width,
+               int* height);
+
+// Encode an RGBA pixel array into a PNG.
+bool EncodeRGBAPNG(const unsigned char* input,
+                   int width,
+                   int height,
+                   int row_byte_width,
+                   std::vector<unsigned char>* output);
+
+// Encode an BGRA pixel array into a PNG.
+bool EncodeBGRAPNG(const unsigned char* input,
+                   int width,
+                   int height,
+                   int row_byte_width,
+                   bool discard_transparency,
+                   std::vector<unsigned char>* output);
+
+}  // namespace image_diff_png
+
+#endif  // TESTING_IMAGE_DIFF_IMAGE_DIFF_PNG_H_