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>

6 files changed, 5 insertions, 1074 deletions

diff --git a/samples/BUILD.gn b/samples/BUILD.gn
index 779d4f3f31..59ab4b4a11 100644
--- a/samples/BUILD.gn
+++ b/samples/BUILD.gn
@@ -8,7 +8,6 @@ import("../pdfium.gni")
 group("samples") {
   testonly = true
   deps = [
-    ":pdfium_diff",
     ":pdfium_test",
   ]
 }
@@ -46,19 +45,15 @@ config("pdfium_samples_config") {
 executable("pdfium_test") {
   testonly = true
   sources = [
-    "image_diff_png.cc",
-    "image_diff_png.h",
     "pdfium_test.cc",
   ]
   deps = [
+    "../:image_diff",
     "../:pdfium",
     "../:test_support",
     "//build/config:exe_and_shlib_deps",
     "//build/win:default_exe_manifest",
   ]
-  if (!pdf_enable_xfa) {
-    deps += [ "../third_party:fx_lpng" ]
-  }
   if (pdf_enable_v8) {
     deps += [ "//v8:v8_libplatform" ]
     include_dirs = [
@@ -72,25 +67,3 @@ executable("pdfium_test") {
   }
   configs += [ ":pdfium_samples_config" ]
 }
-
-executable("pdfium_diff") {
-  testonly = true
-  sources = [
-    "image_diff.cc",
-    "image_diff_png.cc",
-    "image_diff_png.h",
-  ]
-  deps = [
-    "../:pdfium",
-    "//build/config:exe_and_shlib_deps",
-    "//build/win:default_exe_manifest",
-  ]
-  if (!pdf_enable_xfa) {
-    deps += [ "../third_party:fx_lpng" ]
-  }
-  configs -= [ "//build/config/compiler:chromium_code" ]
-  configs += [
-    ":pdfium_samples_config",
-    "//build/config/compiler:no_chromium_code",
-  ]
-}
diff --git a/samples/DEPS b/samples/DEPS
index 0a426d6e9c..26f9ee22eb 100644
--- a/samples/DEPS
+++ b/samples/DEPS
@@ -1,9 +1,5 @@
 include_rules = [
   '+public',
-  '+third_party/libpng16',
   '+third_party/skia/include',
-  '+third_party/zlib',
   '+v8',
-  '+core/fdrm/crypto/fx_crypt.h',
-  '+core/fxcrt/fx_memory.h',
 ]
diff --git a/samples/image_diff.cc b/samples/image_diff.cc
deleted file mode 100644
index 21460f5a62..0000000000
--- a/samples/image_diff.cc
+++ /dev/null
@@ -1,352 +0,0 @@
-// Copyright (c) 2011 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.
-
-// This file input format is based loosely on
-// Tools/DumpRenderTree/ImageDiff.m
-
-// The exact format of this tool's output to stdout is important, to match
-// what the run-webkit-tests script expects.
-
-#include <assert.h>
-#include <stdint.h>
-#include <stdio.h>
-#include <string.h>
-
-#include <algorithm>
-#include <iostream>
-#include <map>
-#include <string>
-#include <vector>
-
-#include "core/fxcrt/fx_memory.h"
-#include "samples/image_diff_png.h"
-#include "third_party/base/logging.h"
-#include "third_party/base/numerics/safe_conversions.h"
-
-#if defined(OS_WIN)
-#include <windows.h>
-#endif
-
-// Return codes used by this utility.
-static const int kStatusSame = 0;
-static const int kStatusDifferent = 1;
-static const int kStatusError = 2;
-
-// Color codes.
-static const uint32_t RGBA_RED = 0x000000ff;
-static const uint32_t RGBA_ALPHA = 0xff000000;
-
-class Image {
- public:
-  Image() : w_(0), h_(0) {
-  }
-
-  Image(const Image& image)
-      : w_(image.w_),
-        h_(image.h_),
-        data_(image.data_) {
-  }
-
-  bool has_image() const {
-    return w_ > 0 && h_ > 0;
-  }
-
-  int w() const {
-    return w_;
-  }
-
-  int h() const {
-    return h_;
-  }
-
-  const unsigned char* data() const {
-    return &data_.front();
-  }
-
-  // Creates the image from the given filename on disk, and returns true on
-  // success.
-  bool CreateFromFilename(const std::string& path) {
-    FILE* f = fopen(path.c_str(), "rb");
-    if (!f)
-      return false;
-
-    std::vector<unsigned char> compressed;
-    const size_t kBufSize = 1024;
-    unsigned char buf[kBufSize];
-    size_t num_read = 0;
-    while ((num_read = fread(buf, 1, kBufSize, f)) > 0) {
-      compressed.insert(compressed.end(), buf, buf + num_read);
-    }
-
-    fclose(f);
-
-    if (!image_diff_png::DecodePNG(compressed.data(), compressed.size(), &data_,
-                                   &w_, &h_)) {
-      Clear();
-      return false;
-    }
-    return true;
-  }
-
-  void Clear() {
-    w_ = h_ = 0;
-    data_.clear();
-  }
-
-  // Returns the RGBA value of the pixel at the given location
-  uint32_t pixel_at(int x, int y) const {
-    if (!pixel_in_bounds(x, y))
-      return 0;
-    return *reinterpret_cast<const uint32_t*>(&(data_[pixel_address(x, y)]));
-  }
-
-  void set_pixel_at(int x, int y, uint32_t color) {
-    if (!pixel_in_bounds(x, y))
-      return;
-
-    void* addr = &data_[pixel_address(x, y)];
-    *reinterpret_cast<uint32_t*>(addr) = color;
-  }
-
- private:
-  bool pixel_in_bounds(int x, int y) const {
-    return x >= 0 && x < w_ && y >= 0 && y < h_;
-  }
-
-  size_t pixel_address(int x, int y) const { return (y * w_ + x) * 4; }
-
-  // Pixel dimensions of the image.
-  int w_;
-  int h_;
-
-  std::vector<unsigned char> data_;
-};
-
-float CalculateDifferencePercentage(const Image& actual, int pixels_different) {
-  // Like the WebKit ImageDiff tool, we define percentage different in terms
-  // of the size of the 'actual' bitmap.
-  float total_pixels =
-      static_cast<float>(actual.w()) * static_cast<float>(actual.h());
-  if (total_pixels == 0) {
-    // When the bitmap is empty, they are 100% different.
-    return 100.0f;
-  }
-  return 100.0f * pixels_different / total_pixels;
-}
-
-void CountImageSizeMismatchAsPixelDifference(const Image& baseline,
-                                             const Image& actual,
-                                             int* pixels_different) {
-  int w = std::min(baseline.w(), actual.w());
-  int h = std::min(baseline.h(), actual.h());
-
-  // Count pixels that are a difference in size as also being different.
-  int max_w = std::max(baseline.w(), actual.w());
-  int max_h = std::max(baseline.h(), actual.h());
-  // These pixels are off the right side, not including the lower right corner.
-  *pixels_different += (max_w - w) * h;
-  // These pixels are along the bottom, including the lower right corner.
-  *pixels_different += (max_h - h) * max_w;
-}
-
-float PercentageDifferent(const Image& baseline, const Image& actual) {
-  int w = std::min(baseline.w(), actual.w());
-  int h = std::min(baseline.h(), actual.h());
-
-  // Compute pixels different in the overlap.
-  int pixels_different = 0;
-  for (int y = 0; y < h; ++y) {
-    for (int x = 0; x < w; ++x) {
-      if (baseline.pixel_at(x, y) != actual.pixel_at(x, y))
-        ++pixels_different;
-    }
-  }
-
-  CountImageSizeMismatchAsPixelDifference(baseline, actual, &pixels_different);
-  return CalculateDifferencePercentage(actual, pixels_different);
-}
-
-float HistogramPercentageDifferent(const Image& baseline, const Image& actual) {
-  // TODO(johnme): Consider using a joint histogram instead, as described in
-  // "Comparing Images Using Joint Histograms" by Pass & Zabih
-  // http://www.cs.cornell.edu/~rdz/papers/pz-jms99.pdf
-
-  int w = std::min(baseline.w(), actual.w());
-  int h = std::min(baseline.h(), actual.h());
-
-  // Count occurences of each RGBA pixel value of baseline in the overlap.
-  std::map<uint32_t, int32_t> baseline_histogram;
-  for (int y = 0; y < h; ++y) {
-    for (int x = 0; x < w; ++x) {
-      // hash_map operator[] inserts a 0 (default constructor) if key not found.
-      ++baseline_histogram[baseline.pixel_at(x, y)];
-    }
-  }
-
-  // Compute pixels different in the histogram of the overlap.
-  int pixels_different = 0;
-  for (int y = 0; y < h; ++y) {
-    for (int x = 0; x < w; ++x) {
-      uint32_t actual_rgba = actual.pixel_at(x, y);
-      auto it = baseline_histogram.find(actual_rgba);
-      if (it != baseline_histogram.end() && it->second > 0)
-        --it->second;
-      else
-        ++pixels_different;
-    }
-  }
-
-  CountImageSizeMismatchAsPixelDifference(baseline, actual, &pixels_different);
-  return CalculateDifferencePercentage(actual, pixels_different);
-}
-
-void PrintHelp() {
-  fprintf(stderr,
-    "Usage:\n"
-    "  image_diff [--histogram] <compare file> <reference file>\n"
-    "    Compares two files on disk, returning 0 when they are the same;\n"
-    "    passing \"--histogram\" additionally calculates a diff of the\n"
-    "    RGBA value histograms (which is resistant to shifts in layout)\n"
-    "  image_diff --diff <compare file> <reference file> <output file>\n"
-    "    Compares two files on disk, outputs an image that visualizes the\n"
-    "    difference to <output file>\n");
-}
-
-int CompareImages(const std::string& file1,
-                  const std::string& file2,
-                  bool compare_histograms) {
-  Image actual_image;
-  Image baseline_image;
-
-  if (!actual_image.CreateFromFilename(file1)) {
-    fprintf(stderr, "image_diff: Unable to open file \"%s\"\n", file1.c_str());
-    return kStatusError;
-  }
-  if (!baseline_image.CreateFromFilename(file2)) {
-    fprintf(stderr, "image_diff: Unable to open file \"%s\"\n", file2.c_str());
-    return kStatusError;
-  }
-
-  if (compare_histograms) {
-    float percent = HistogramPercentageDifferent(actual_image, baseline_image);
-    const char* passed = percent > 0.0 ? "failed" : "passed";
-    printf("histogram diff: %01.2f%% %s\n", percent, passed);
-  }
-
-  const char* const diff_name = compare_histograms ? "exact diff" : "diff";
-  float percent = PercentageDifferent(actual_image, baseline_image);
-  const char* const passed = percent > 0.0 ? "failed" : "passed";
-  printf("%s: %01.2f%% %s\n", diff_name, percent, passed);
-
-  if (percent > 0.0) {
-    // failure: The WebKit version also writes the difference image to
-    // stdout, which seems excessive for our needs.
-    return kStatusDifferent;
-  }
-  // success
-  return kStatusSame;
-}
-
-bool CreateImageDiff(const Image& image1, const Image& image2, Image* out) {
-  int w = std::min(image1.w(), image2.w());
-  int h = std::min(image1.h(), image2.h());
-  *out = Image(image1);
-  bool same = (image1.w() == image2.w()) && (image1.h() == image2.h());
-
-  // TODO(estade): do something with the extra pixels if the image sizes
-  // are different.
-  for (int y = 0; y < h; ++y) {
-    for (int x = 0; x < w; ++x) {
-      uint32_t base_pixel = image1.pixel_at(x, y);
-      if (base_pixel != image2.pixel_at(x, y)) {
-        // Set differing pixels red.
-        out->set_pixel_at(x, y, RGBA_RED | RGBA_ALPHA);
-        same = false;
-      } else {
-        // Set same pixels as faded.
-        uint32_t alpha = base_pixel & RGBA_ALPHA;
-        uint32_t new_pixel = base_pixel - ((alpha / 2) & RGBA_ALPHA);
-        out->set_pixel_at(x, y, new_pixel);
-      }
-    }
-  }
-
-  return same;
-}
-
-int DiffImages(const std::string& file1,
-               const std::string& file2,
-               const std::string& out_file) {
-  Image actual_image;
-  Image baseline_image;
-
-  if (!actual_image.CreateFromFilename(file1)) {
-    fprintf(stderr, "image_diff: Unable to open file \"%s\"\n", file1.c_str());
-    return kStatusError;
-  }
-  if (!baseline_image.CreateFromFilename(file2)) {
-    fprintf(stderr, "image_diff: Unable to open file \"%s\"\n", file2.c_str());
-    return kStatusError;
-  }
-
-  Image diff_image;
-  bool same = CreateImageDiff(baseline_image, actual_image, &diff_image);
-  if (same)
-    return kStatusSame;
-
-  std::vector<unsigned char> png_encoding;
-  image_diff_png::EncodeRGBAPNG(
-      diff_image.data(), diff_image.w(), diff_image.h(),
-      diff_image.w() * 4, &png_encoding);
-
-  FILE* f = fopen(out_file.c_str(), "wb");
-  if (!f)
-    return kStatusError;
-
-  size_t size = png_encoding.size();
-  char* ptr = reinterpret_cast<char*>(&png_encoding.front());
-  if (fwrite(ptr, 1, size, f) != size)
-    return kStatusError;
-
-  return kStatusDifferent;
-}
-
-int main(int argc, const char* argv[]) {
-  FXMEM_InitializePartitionAlloc();
-
-  bool histograms = false;
-  bool produce_diff_image = false;
-  std::string filename1;
-  std::string filename2;
-  std::string diff_filename;
-
-  int i;
-  for (i = 1; i < argc; ++i) {
-    const char* arg = argv[i];
-    if (strstr(arg, "--") != arg)
-      break;
-    if (strcmp(arg, "--histogram") == 0) {
-      histograms = true;
-    } else if (strcmp(arg, "--diff") == 0) {
-      produce_diff_image = true;
-    }
-  }
-  if (i < argc)
-    filename1 = argv[i++];
-  if (i < argc)
-    filename2 = argv[i++];
-  if (i < argc)
-    diff_filename = argv[i++];
-
-  if (produce_diff_image) {
-    if (!diff_filename.empty()) {
-      return DiffImages(filename1, filename2, diff_filename);
-    }
-  } else if (!filename2.empty()) {
-    return CompareImages(filename1, filename2, histograms);
-  }
-
-  PrintHelp();
-  return kStatusError;
-}
diff --git a/samples/image_diff_png.cc b/samples/image_diff_png.cc
deleted file mode 100644
index 3d12b7e948..0000000000
--- a/samples/image_diff_png.cc
+++ /dev/null
@@ -1,644 +0,0 @@
-// 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.
-
-// This is a duplicate of chromium's src/tools/imagediff/image_diff_png.cc
-// that has been modified to build in a pdfium environment, which itself
-// was duplicated as follows:
-
-// This is a duplicate of ui/gfx/codec/png_codec.cc, after removing code related
-// to Skia, that we can use when running layout tests with minimal dependencies.
-
-#include "samples/image_diff_png.h"
-
-#include <stdlib.h>
-#include <string.h>
-
-#include <string>
-
-#include "third_party/base/logging.h"
-#include "third_party/libpng16/png.h"
-#include "third_party/zlib/zlib.h"
-
-namespace image_diff_png {
-
-namespace {
-
-enum ColorFormat {
-  // 3 bytes per pixel (packed), in RGB order regardless of endianness.
-  // This is the native JPEG format.
-  FORMAT_RGB,
-
-  // 4 bytes per pixel, in RGBA order in memory regardless of endianness.
-  FORMAT_RGBA,
-
-  // 4 bytes per pixel, in BGRA order in memory regardless of endianness.
-  // This is the default Windows DIB order.
-  FORMAT_BGRA,
-};
-
-// Represents a comment in the tEXt ancillary chunk of the png.
-struct Comment {
-  std::string key;
-  std::string text;
-};
-
-// Converts BGRA->RGBA and RGBA->BGRA.
-void ConvertBetweenBGRAandRGBA(const unsigned char* input, int pixel_width,
-                               unsigned char* output, bool* is_opaque) {
-  for (int x = 0; x < pixel_width; x++) {
-    const unsigned char* pixel_in = &input[x * 4];
-    unsigned char* pixel_out = &output[x * 4];
-    pixel_out[0] = pixel_in[2];
-    pixel_out[1] = pixel_in[1];
-    pixel_out[2] = pixel_in[0];
-    pixel_out[3] = pixel_in[3];
-  }
-}
-
-void ConvertRGBAtoRGB(const unsigned char* rgba, int pixel_width,
-                      unsigned char* rgb, bool* is_opaque) {
-  for (int x = 0; x < pixel_width; x++) {
-    const unsigned char* pixel_in = &rgba[x * 4];
-    unsigned char* pixel_out = &rgb[x * 3];
-    pixel_out[0] = pixel_in[0];
-    pixel_out[1] = pixel_in[1];
-    pixel_out[2] = pixel_in[2];
-  }
-}
-
-}  // namespace
-
-// Decoder
-//
-// This code is based on WebKit libpng interface (PNGImageDecoder), which is
-// in turn based on the Mozilla png decoder.
-
-namespace {
-
-// Gamma constants: We assume we're on Windows which uses a gamma of 2.2.
-const double kMaxGamma = 21474.83;  // Maximum gamma accepted by png library.
-const double kDefaultGamma = 2.2;
-const double kInverseGamma = 1.0 / kDefaultGamma;
-
-class PngDecoderState {
- public:
-  // Output is a vector<unsigned char>.
-  PngDecoderState(ColorFormat ofmt, std::vector<unsigned char>* o)
-      : output_format(ofmt),
-        output_channels(0),
-        is_opaque(true),
-        output(o),
-        row_converter(NULL),
-        width(0),
-        height(0),
-        done(false) {
-  }
-
-  ColorFormat output_format;
-  int output_channels;
-
-  // Used during the reading of an SkBitmap. Defaults to true until we see a
-  // pixel with anything other than an alpha of 255.
-  bool is_opaque;
-
-  // An intermediary buffer for decode output.
-  std::vector<unsigned char>* output;
-
-  // Called to convert a row from the library to the correct output format.
-  // When NULL, no conversion is necessary.
-  void (*row_converter)(const unsigned char* in, int w, unsigned char* out,
-                        bool* is_opaque);
-
-  // Size of the image, set in the info callback.
-  int width;
-  int height;
-
-  // Set to true when we've found the end of the data.
-  bool done;
-};
-
-void ConvertRGBtoRGBA(const unsigned char* rgb, int pixel_width,
-                      unsigned char* rgba, bool* is_opaque) {
-  for (int x = 0; x < pixel_width; x++) {
-    const unsigned char* pixel_in = &rgb[x * 3];
-    unsigned char* pixel_out = &rgba[x * 4];
-    pixel_out[0] = pixel_in[0];
-    pixel_out[1] = pixel_in[1];
-    pixel_out[2] = pixel_in[2];
-    pixel_out[3] = 0xff;
-  }
-}
-
-void ConvertRGBtoBGRA(const unsigned char* rgb, int pixel_width,
-                      unsigned char* bgra, bool* is_opaque) {
-  for (int x = 0; x < pixel_width; x++) {
-    const unsigned char* pixel_in = &rgb[x * 3];
-    unsigned char* pixel_out = &bgra[x * 4];
-    pixel_out[0] = pixel_in[2];
-    pixel_out[1] = pixel_in[1];
-    pixel_out[2] = pixel_in[0];
-    pixel_out[3] = 0xff;
-  }
-}
-
-// Called when the png header has been read. This code is based on the WebKit
-// PNGImageDecoder
-void DecodeInfoCallback(png_struct* png_ptr, png_info* info_ptr) {
-  PngDecoderState* state = static_cast<PngDecoderState*>(
-      png_get_progressive_ptr(png_ptr));
-
-  int bit_depth, color_type, interlace_type, compression_type;
-  int filter_type, channels;
-  png_uint_32 w, h;
-  png_get_IHDR(png_ptr, info_ptr, &w, &h, &bit_depth, &color_type,
-               &interlace_type, &compression_type, &filter_type);
-
-  // Bounds check. When the image is unreasonably big, we'll error out and
-  // end up back at the setjmp call when we set up decoding.  "Unreasonably big"
-  // means "big enough that w * h * 32bpp might overflow an int"; we choose this
-  // threshold to match WebKit and because a number of places in code assume
-  // that an image's size (in bytes) fits in a (signed) int.
-  unsigned long long total_size =
-      static_cast<unsigned long long>(w) * static_cast<unsigned long long>(h);
-  if (total_size > ((1 << 29) - 1))
-    longjmp(png_jmpbuf(png_ptr), 1);
-  state->width = static_cast<int>(w);
-  state->height = static_cast<int>(h);
-
-  // Expand to ensure we use 24-bit for RGB and 32-bit for RGBA.
-  if (color_type == PNG_COLOR_TYPE_PALETTE ||
-      (color_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8))
-    png_set_expand(png_ptr);
-
-  // Transparency for paletted images.
-  if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS))
-    png_set_expand(png_ptr);
-
-  // Convert 16-bit to 8-bit.
-  if (bit_depth == 16)
-    png_set_strip_16(png_ptr);
-
-  // Expand grayscale to RGB.
-  if (color_type == PNG_COLOR_TYPE_GRAY ||
-      color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
-    png_set_gray_to_rgb(png_ptr);
-
-  // Deal with gamma and keep it under our control.
-  double gamma;
-  if (png_get_gAMA(png_ptr, info_ptr, &gamma)) {
-    if (gamma <= 0.0 || gamma > kMaxGamma) {
-      gamma = kInverseGamma;
-      png_set_gAMA(png_ptr, info_ptr, gamma);
-    }
-    png_set_gamma(png_ptr, kDefaultGamma, gamma);
-  } else {
-    png_set_gamma(png_ptr, kDefaultGamma, kInverseGamma);
-  }
-
-  // Tell libpng to send us rows for interlaced pngs.
-  if (interlace_type == PNG_INTERLACE_ADAM7)
-    png_set_interlace_handling(png_ptr);
-
-  // Update our info now
-  png_read_update_info(png_ptr, info_ptr);
-  channels = png_get_channels(png_ptr, info_ptr);
-
-  // Pick our row format converter necessary for this data.
-  if (channels == 3) {
-    switch (state->output_format) {
-      case FORMAT_RGB:
-        state->row_converter = NULL;  // no conversion necessary
-        state->output_channels = 3;
-        break;
-      case FORMAT_RGBA:
-        state->row_converter = &ConvertRGBtoRGBA;
-        state->output_channels = 4;
-        break;
-      case FORMAT_BGRA:
-        state->row_converter = &ConvertRGBtoBGRA;
-        state->output_channels = 4;
-        break;
-      default:
-        NOTREACHED();
-        break;
-    }
-  } else if (channels == 4) {
-    switch (state->output_format) {
-      case FORMAT_RGB:
-        state->row_converter = &ConvertRGBAtoRGB;
-        state->output_channels = 3;
-        break;
-      case FORMAT_RGBA:
-        state->row_converter = NULL;  // no conversion necessary
-        state->output_channels = 4;
-        break;
-      case FORMAT_BGRA:
-        state->row_converter = &ConvertBetweenBGRAandRGBA;
-        state->output_channels = 4;
-        break;
-      default:
-        NOTREACHED();
-        break;
-    }
-  } else {
-    NOTREACHED();
-    longjmp(png_jmpbuf(png_ptr), 1);
-  }
-
-  state->output->resize(
-      state->width * state->output_channels * state->height);
-}
-
-void DecodeRowCallback(png_struct* png_ptr, png_byte* new_row,
-                       png_uint_32 row_num, int pass) {
-  PngDecoderState* state = static_cast<PngDecoderState*>(
-      png_get_progressive_ptr(png_ptr));
-
-  if (static_cast<int>(row_num) > state->height) {
-    NOTREACHED();
-    return;
-  }
-
-  unsigned char* base = NULL;
-  base = &state->output->front();
-
-  unsigned char* dest = &base[state->width * state->output_channels * row_num];
-  if (state->row_converter)
-    state->row_converter(new_row, state->width, dest, &state->is_opaque);
-  else
-    memcpy(dest, new_row, state->width * state->output_channels);
-}
-
-void DecodeEndCallback(png_struct* png_ptr, png_info* info) {
-  PngDecoderState* state = static_cast<PngDecoderState*>(
-      png_get_progressive_ptr(png_ptr));
-
-  // Mark the image as complete, this will tell the Decode function that we
-  // have successfully found the end of the data.
-  state->done = true;
-}
-
-// Automatically destroys the given read structs on destruction to make
-// cleanup and error handling code cleaner.
-class PngReadStructDestroyer {
- public:
-  PngReadStructDestroyer(png_struct** ps, png_info** pi) : ps_(ps), pi_(pi) {
-  }
-  ~PngReadStructDestroyer() {
-    png_destroy_read_struct(ps_, pi_, NULL);
-  }
- private:
-  png_struct** ps_;
-  png_info** pi_;
-};
-
-bool BuildPNGStruct(const unsigned char* input, size_t input_size,
-                    png_struct** png_ptr, png_info** info_ptr) {
-  if (input_size < 8)
-    return false;  // Input data too small to be a png
-
-  // Have libpng check the signature, it likes the first 8 bytes.
-  if (png_sig_cmp(const_cast<unsigned char*>(input), 0, 8) != 0)
-    return false;
-
-  *png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
-  if (!*png_ptr)
-    return false;
-
-  *info_ptr = png_create_info_struct(*png_ptr);
-  if (!*info_ptr) {
-    png_destroy_read_struct(png_ptr, NULL, NULL);
-    return false;
-  }
-
-  return true;
-}
-
-}  // namespace
-
-// static
-bool Decode(const unsigned char* input, size_t input_size,
-                      ColorFormat format, std::vector<unsigned char>* output,
-                      int* w, int* h) {
-  png_struct* png_ptr = NULL;
-  png_info* info_ptr = NULL;
-  if (!BuildPNGStruct(input, input_size, &png_ptr, &info_ptr))
-    return false;
-
-  PngReadStructDestroyer destroyer(&png_ptr, &info_ptr);
-  if (setjmp(png_jmpbuf(png_ptr))) {
-    // The destroyer will ensure that the structures are cleaned up in this
-    // case, even though we may get here as a jump from random parts of the
-    // PNG library called below.
-    return false;
-  }
-
-  PngDecoderState state(format, output);
-
-  png_set_progressive_read_fn(png_ptr, &state, &DecodeInfoCallback,
-                              &DecodeRowCallback, &DecodeEndCallback);
-  png_process_data(png_ptr,
-                   info_ptr,
-                   const_cast<unsigned char*>(input),
-                   input_size);
-
-  if (!state.done) {
-    // Fed it all the data but the library didn't think we got all the data, so
-    // this file must be truncated.
-    output->clear();
-    return false;
-  }
-
-  *w = state.width;
-  *h = state.height;
-  return true;
-}
-
-// Encoder
-//
-// This section of the code is based on nsPNGEncoder.cpp in Mozilla
-// (Copyright 2005 Google Inc.)
-
-namespace {
-
-// Passed around as the io_ptr in the png structs so our callbacks know where
-// to write data.
-struct PngEncoderState {
-  explicit PngEncoderState(std::vector<unsigned char>* o) : out(o) {}
-  std::vector<unsigned char>* out;
-};
-
-// Called by libpng to flush its internal buffer to ours.
-void EncoderWriteCallback(png_structp png, png_bytep data, png_size_t size) {
-  PngEncoderState* state = static_cast<PngEncoderState*>(png_get_io_ptr(png));
-  size_t old_size = state->out->size();
-  state->out->resize(old_size + size);
-  memcpy(&(*state->out)[old_size], data, size);
-}
-
-void FakeFlushCallback(png_structp png) {
-  // We don't need to perform any flushing since we aren't doing real IO, but
-  // we're required to provide this function by libpng.
-}
-
-void ConvertBGRAtoRGB(const unsigned char* bgra, int pixel_width,
-                      unsigned char* rgb, bool* is_opaque) {
-  for (int x = 0; x < pixel_width; x++) {
-    const unsigned char* pixel_in = &bgra[x * 4];
-    unsigned char* pixel_out = &rgb[x * 3];
-    pixel_out[0] = pixel_in[2];
-    pixel_out[1] = pixel_in[1];
-    pixel_out[2] = pixel_in[0];
-  }
-}
-
-#ifdef PNG_TEXT_SUPPORTED
-
-inline char* strdup(const char* str) {
-#if defined(OS_WIN)
-  return _strdup(str);
-#else
-  return ::strdup(str);
-#endif
-}
-
-class CommentWriter {
- public:
-  explicit CommentWriter(const std::vector<Comment>& comments)
-      : comments_(comments),
-        png_text_(new png_text[comments.size()]) {
-    for (size_t i = 0; i < comments.size(); ++i)
-      AddComment(i, comments[i]);
-  }
-
-  ~CommentWriter() {
-    for (size_t i = 0; i < comments_.size(); ++i) {
-      free(png_text_[i].key);
-      free(png_text_[i].text);
-    }
-    delete [] png_text_;
-  }
-
-  bool HasComments() {
-    return !comments_.empty();
-  }
-
-  png_text* get_png_text() {
-    return png_text_;
-  }
-
-  int size() {
-    return static_cast<int>(comments_.size());
-  }
-
- private:
-  void AddComment(size_t pos, const Comment& comment) {
-    png_text_[pos].compression = PNG_TEXT_COMPRESSION_NONE;
-    // A PNG comment's key can only be 79 characters long.
-    if (comment.key.length() > 79)
-      return;
-    png_text_[pos].key = strdup(comment.key.substr(0, 78).c_str());
-    png_text_[pos].text = strdup(comment.text.c_str());
-    png_text_[pos].text_length = comment.text.length();
-#ifdef PNG_iTXt_SUPPORTED
-    png_text_[pos].itxt_length = 0;
-    png_text_[pos].lang = 0;
-    png_text_[pos].lang_key = 0;
-#endif
-  }
-
-  const std::vector<Comment> comments_;
-  png_text* png_text_;
-};
-#endif  // PNG_TEXT_SUPPORTED
-
-// The type of functions usable for converting between pixel formats.
-typedef void (*FormatConverter)(const unsigned char* in, int w,
-                                unsigned char* out, bool* is_opaque);
-
-// libpng uses a wacky setjmp-based API, which makes the compiler nervous.
-// We constrain all of the calls we make to libpng where the setjmp() is in
-// place to this function.
-// Returns true on success.
-bool DoLibpngWrite(png_struct* png_ptr, png_info* info_ptr,
-                   PngEncoderState* state,
-                   int width, int height, int row_byte_width,
-                   const unsigned char* input, int compression_level,
-                   int png_output_color_type, int output_color_components,
-                   FormatConverter converter,
-                   const std::vector<Comment>& comments) {
-#ifdef PNG_TEXT_SUPPORTED
-  CommentWriter comment_writer(comments);
-#endif
-  unsigned char* row_buffer = NULL;
-
-  // Make sure to not declare any locals here -- locals in the presence
-  // of setjmp() in C++ code makes gcc complain.
-
-  if (setjmp(png_jmpbuf(png_ptr))) {
-    delete[] row_buffer;
-    return false;
-  }
-
-  png_set_compression_level(png_ptr, compression_level);
-
-  // Set our callback for libpng to give us the data.
-  png_set_write_fn(png_ptr, state, EncoderWriteCallback, FakeFlushCallback);
-
-  png_set_IHDR(png_ptr, info_ptr, width, height, 8, png_output_color_type,
-               PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_DEFAULT,
-               PNG_FILTER_TYPE_DEFAULT);
-
-#ifdef PNG_TEXT_SUPPORTED
-  if (comment_writer.HasComments()) {
-    png_set_text(png_ptr, info_ptr, comment_writer.get_png_text(),
-                 comment_writer.size());
-  }
-#endif
-
-  png_write_info(png_ptr, info_ptr);
-
-  if (!converter) {
-    // No conversion needed, give the data directly to libpng.
-    for (int y = 0; y < height; y ++) {
-      png_write_row(png_ptr,
-                    const_cast<unsigned char*>(&input[y * row_byte_width]));
-    }
-  } else {
-    // Needs conversion using a separate buffer.
-    row_buffer = new unsigned char[width * output_color_components];
-    for (int y = 0; y < height; y ++) {
-      converter(&input[y * row_byte_width], width, row_buffer, NULL);
-      png_write_row(png_ptr, row_buffer);
-    }
-    delete[] row_buffer;
-  }
-
-  png_write_end(png_ptr, info_ptr);
-  return true;
-}
-
-}  // namespace
-
-// static
-bool EncodeWithCompressionLevel(const unsigned char* input, ColorFormat format,
-                                const int width, const int height,
-                                int row_byte_width,
-                                bool discard_transparency,
-                                const std::vector<Comment>& comments,
-                                int compression_level,
-                                std::vector<unsigned char>* output) {
-  // Run to convert an input row into the output row format, NULL means no
-  // conversion is necessary.
-  FormatConverter converter = NULL;
-
-  int input_color_components, output_color_components;
-  int png_output_color_type;
-  switch (format) {
-    case FORMAT_RGB:
-      input_color_components = 3;
-      output_color_components = 3;
-      png_output_color_type = PNG_COLOR_TYPE_RGB;
-      discard_transparency = false;
-      break;
-
-    case FORMAT_RGBA:
-      input_color_components = 4;
-      if (discard_transparency) {
-        output_color_components = 3;
-        png_output_color_type = PNG_COLOR_TYPE_RGB;
-        converter = ConvertRGBAtoRGB;
-      } else {
-        output_color_components = 4;
-        png_output_color_type = PNG_COLOR_TYPE_RGB_ALPHA;
-        converter = NULL;
-      }
-      break;
-
-    case FORMAT_BGRA:
-      input_color_components = 4;
-      if (discard_transparency) {
-        output_color_components = 3;
-        png_output_color_type = PNG_COLOR_TYPE_RGB;
-        converter = ConvertBGRAtoRGB;
-      } else {
-        output_color_components = 4;
-        png_output_color_type = PNG_COLOR_TYPE_RGB_ALPHA;
-        converter = ConvertBetweenBGRAandRGBA;
-      }
-      break;
-
-    default:
-      NOTREACHED();
-      return false;
-  }
-
-  // Row stride should be at least as long as the length of the data.
-  if (input_color_components * width < row_byte_width)
-    return false;
-
-  png_struct* png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING,
-                                                NULL, NULL, NULL);
-  if (!png_ptr)
-    return false;
-  png_info* info_ptr = png_create_info_struct(png_ptr);
-  if (!info_ptr) {
-    png_destroy_write_struct(&png_ptr, NULL);
-    return false;
-  }
-
-  PngEncoderState state(output);
-  bool success = DoLibpngWrite(png_ptr, info_ptr, &state,
-                               width, height, row_byte_width,
-                               input, compression_level, png_output_color_type,
-                               output_color_components, converter, comments);
-  png_destroy_write_struct(&png_ptr, &info_ptr);
-
-  return success;
-}
-
-// static
-bool Encode(const unsigned char* input, ColorFormat format,
-            const int width, const int height, int row_byte_width,
-            bool discard_transparency,
-            const std::vector<Comment>& comments,
-            std::vector<unsigned char>* output) {
-  return EncodeWithCompressionLevel(input, format, width, height,
-                                    row_byte_width,
-                                    discard_transparency,
-                                    comments, Z_DEFAULT_COMPRESSION,
-                                    output);
-}
-
-// 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) {
-  return Decode(input, input_size, FORMAT_RGBA, output, width, 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) {
-  return Encode(input, FORMAT_RGBA,
-      width, height, row_byte_width, false,
-      std::vector<Comment>(), 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) {
-  return Encode(input, FORMAT_BGRA,
-      width, height, row_byte_width, discard_transparency,
-      std::vector<Comment>(), output);
-}
-
-}  // namespace image_diff_png
diff --git a/samples/image_diff_png.h b/samples/image_diff_png.h
deleted file mode 100644
index 7bb395a4a5..0000000000
--- a/samples/image_diff_png.h
+++ /dev/null
@@ -1,38 +0,0 @@
-// 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 SAMPLES_IMAGE_DIFF_PNG_H_
-#define SAMPLES_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  // SAMPLES_IMAGE_DIFF_PNG_H_
diff --git a/samples/pdfium_test.cc b/samples/pdfium_test.cc
index a53edb77d3..ccd57a7e6a 100644
--- a/samples/pdfium_test.cc
+++ b/samples/pdfium_test.cc
@@ -18,7 +18,6 @@
 #define _SKIA_SUPPORT_
 #endif
 
-#include "core/fdrm/crypto/fx_crypt.h"
 #include "public/cpp/fpdf_deleters.h"
 #include "public/fpdf_annot.h"
 #include "public/fpdf_dataavail.h"
@@ -28,7 +27,7 @@
 #include "public/fpdf_structtree.h"
 #include "public/fpdf_text.h"
 #include "public/fpdfview.h"
-#include "samples/image_diff_png.h"
+#include "testing/image_diff/image_diff_png.h"
 #include "testing/test_support.h"
 #include "third_party/base/logging.h"
 
@@ -121,12 +120,9 @@ static bool CheckDimensions(int stride, int width, int height) {
 
 static void OutputMD5Hash(const char* file_name, const char* buffer, int len) {
   // Get the MD5 hash and write it to stdout.
-  uint8_t digest[16];
-  CRYPT_MD5Generate(reinterpret_cast<const uint8_t*>(buffer), len, digest);
-  printf("MD5:%s:", file_name);
-  for (int i = 0; i < 16; i++)
-    printf("%02x", digest[i]);
-  printf("\n");
+  std::string hash =
+      GenerateMD5Base16(reinterpret_cast<const uint8_t*>(buffer), len);
+  printf("MD5:%s:%s\n", file_name, hash.c_str());
 }
 
 static std::string WritePpm(const char* pdf_name,