Revert "Update libpng from 1.6.22 -> 1.6.34"chromium/3543

This reverts commit 6b2e2f0ec7c5f629c5270d14c2339197af7392d8.

Reason for revert: Broke Chromium integration.

Original change's description:
> Update libpng from 1.6.22 -> 1.6.34
> 
> Updates third_party/libpng16 to Chromium's third_party/libpng @
> e87a02987101e2dbe319a4aba6b52470f7624b4a and applies PDFium specific
> patches.
> 
> BUG=chromium:880322
> 
> Change-Id: I6724f55099c70a79da6d6e4863b9c6c9157ec571
> Reviewed-on: https://pdfium-review.googlesource.com/41910
> Reviewed-by: Lei Zhang <thestig@chromium.org>
> Commit-Queue: Ryan Harrison <rharrison@chromium.org>

TBR=thestig@chromium.org,rharrison@chromium.org

Change-Id: I2fd1f78e5d07ca983b2430bf078544185292ee1d
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: chromium:880322
Reviewed-on: https://pdfium-review.googlesource.com/41970
Reviewed-by: Lei Zhang <thestig@chromium.org>
Commit-Queue: Lei Zhang <thestig@chromium.org>

2 files changed, 3 insertions, 140 deletions

diff --git a/third_party/libpng16/arm/filter_neon.S b/third_party/libpng16/arm/filter_neon.S
index 000764cd21..3b061d6bbf 100644
--- a/third_party/libpng16/arm/filter_neon.S
+++ b/third_party/libpng16/arm/filter_neon.S
@@ -1,9 +1,9 @@
 
 /* filter_neon.S - NEON optimised filter functions
  *
- * Copyright (c) 2014,2017 Glenn Randers-Pehrson
+ * Copyright (c) 2014 Glenn Randers-Pehrson
  * Written by Mans Rullgard, 2011.
- * Last changed in libpng 1.6.31 [July 27, 2017]
+ * Last changed in libpng 1.6.16 [December 22, 2014]
  *
  * This code is released under the libpng license.
  * For conditions of distribution and use, see the disclaimer
@@ -16,7 +16,7 @@
 #define PNG_VERSION_INFO_ONLY
 #include "../pngpriv.h"
 
-#if (defined(__linux__) || defined(__FreeBSD__)) && defined(__ELF__)
+#if defined(__linux__) && defined(__ELF__)
 .section .note.GNU-stack,"",%progbits /* mark stack as non-executable */
 #endif
 
diff --git a/third_party/libpng16/arm/palette_neon_intrinsics.c b/third_party/libpng16/arm/palette_neon_intrinsics.c
deleted file mode 100644
index 703b9ff250..0000000000
--- a/third_party/libpng16/arm/palette_neon_intrinsics.c
+++ /dev/null
@@ -1,137 +0,0 @@
-/* palette_neon_intrinsics.c - NEON optimised palette expansion functions
- *
- * Copyright (c) 2017 The Chromium Authors. All rights reserved.
- * Written by Richard Townsend <Richard.Townsend@arm.com>, February 2017.
- *
- * This code is released under the libpng license.
- * For conditions of distribution and use, see the disclaimer
- * and license in png.h
- */
-
-#include "../pngpriv.h"
-
-#if PNG_ARM_NEON_IMPLEMENTATION == 1
-
-#include <arm_neon.h>
-
-/* Build an RGBA palette from the RGB and separate alpha palettes. */
-void
-png_riffle_palette_rgba(png_structrp png_ptr, png_row_infop row_info)
-{
-   png_const_colorp palette = png_ptr->palette;
-   png_bytep riffled_palette = png_ptr->riffled_palette;
-   png_const_bytep trans_alpha = png_ptr->trans_alpha;
-   int num_trans = png_ptr->num_trans;
-
-   if (row_info->bit_depth != 8) {
-      png_error(png_ptr, "bit_depth must be 8 for png_riffle_palette_rgba");
-      return;
-   }
-
-   /* Initially black, opaque. */
-   uint8x16x4_t w = {{
-      vdupq_n_u8(0x00),
-      vdupq_n_u8(0x00),
-      vdupq_n_u8(0x00),
-      vdupq_n_u8(0xff),
-   }};
-
-   int i;
-   /* First, riffle the RGB colours into a RGBA palette, the A value is
-    * set to opaque for now. */
-   for (i = 0; i < (1 << row_info->bit_depth); i += 16) {
-      uint8x16x3_t v = vld3q_u8((png_const_bytep)(palette + i));
-      w.val[0] = v.val[0];
-      w.val[1] = v.val[1];
-      w.val[2] = v.val[2];
-      vst4q_u8(riffled_palette + (i << 2), w);
-   }
-
-   /* Fix up the missing transparency values. */
-   for (i = 0; i < num_trans; i++) {
-      riffled_palette[(i << 2) + 3] = trans_alpha[i];
-   }
-}
-
-
-/* Expands a palettized row into RGBA. */
-int
-png_do_expand_palette_neon_rgba(png_structrp png_ptr, png_row_infop row_info,
-   png_const_bytep row, const png_bytepp ssp, const png_bytepp ddp)
-{
-
-   png_uint_32 row_width = row_info->width;
-   const png_uint_32 *riffled_palette = (const png_uint_32*)png_ptr->riffled_palette;
-   const png_int_32 pixels_per_chunk = 4;
-
-   if (row_width < pixels_per_chunk) {
-      return 0;
-   }
-
-   /* This function originally gets the last byte of the output row.
-      The NEON part writes forward from a given position, so we have
-      to seek this back by 4 pixels x 4 bytes. */
-   *ddp = *ddp - ((pixels_per_chunk * sizeof(png_uint_32)) - 1);
-
-   int i;
-   for (i = 0; i < row_width; i += pixels_per_chunk) {
-      uint32x4_t cur;
-      png_bytep sp = *ssp - i, dp = *ddp - (i << 2);
-      cur = vld1q_dup_u32 (riffled_palette + *(sp - 3));
-      cur = vld1q_lane_u32(riffled_palette + *(sp - 2), cur, 1);
-      cur = vld1q_lane_u32(riffled_palette + *(sp - 1), cur, 2);
-      cur = vld1q_lane_u32(riffled_palette + *(sp - 0), cur, 3);
-      vst1q_u32((void *)dp, cur);
-   }
-   if (i != row_width) {
-      i -= pixels_per_chunk; /* Remove the amount that wasn't processed. */
-   }
-
-   /* Decrement output pointers. */
-   *ssp = *ssp - i;
-   *ddp = *ddp - (i << 2);
-   return i;
-}
-
-/* Expands a palettized row into RGB format. */
-int
-png_do_expand_palette_neon_rgb(png_structrp png_ptr, png_row_infop row_info,
-   png_const_bytep row, const png_bytepp ssp, const png_bytepp ddp)
-{
-   png_uint_32 row_width = row_info->width;
-   png_const_bytep palette = (png_const_bytep)png_ptr->palette;
-   const png_uint_32 pixels_per_chunk = 8;
-
-   if (row_width <= pixels_per_chunk) {
-      return 0;
-   }
-
-   /* Seeking this back by 8 pixels x 3 bytes. */
-   *ddp = *ddp - ((pixels_per_chunk * sizeof(png_color)) - 1);
-
-   int i;
-   for (i = 0; i < row_width; i += pixels_per_chunk) {
-      uint8x8x3_t cur;
-      png_bytep sp = *ssp - i, dp = *ddp - ((i << 1) + i);
-      cur = vld3_dup_u8(palette + sizeof(png_color) * (*(sp - 7)));
-      cur = vld3_lane_u8(palette + sizeof(png_color) * (*(sp - 6)), cur, 1);
-      cur = vld3_lane_u8(palette + sizeof(png_color) * (*(sp - 5)), cur, 2);
-      cur = vld3_lane_u8(palette + sizeof(png_color) * (*(sp - 4)), cur, 3);
-      cur = vld3_lane_u8(palette + sizeof(png_color) * (*(sp - 3)), cur, 4);
-      cur = vld3_lane_u8(palette + sizeof(png_color) * (*(sp - 2)), cur, 5);
-      cur = vld3_lane_u8(palette + sizeof(png_color) * (*(sp - 1)), cur, 6);
-      cur = vld3_lane_u8(palette + sizeof(png_color) * (*(sp - 0)), cur, 7);
-      vst3_u8((void *)dp, cur);
-   }
-
-   if (i != row_width) {
-      i -= pixels_per_chunk; /* Remove the amount that wasn't processed. */
-   }
-
-   /* Decrement output pointers. */
-   *ssp = *ssp - i;
-   *ddp = *ddp - ((i << 1) + i);
-   return i;
-}
-
-#endif /* PNG_ARM_NEON_IMPLEMENTATION */