Make SkImageDecoder_libpng be compilable with Chromium libpng

Chromium has libpng with pngusr.h that disables certain functionality with
defines. Use those defines when compiling SkImageDecoder_libpng.cpp.

This makes it possible to use Skia PNG decoder and encoder when compiling dm
with Chromium. Skia PNG decoder and encoder of course is not compiled to the
skia library, but to dm with Chromium.

BUG=skia:2992

Review URL: https://codereview.chromium.org/645883004

1 files changed, 10 insertions, 2 deletions

diff --git a/src/images/SkImageDecoder_libpng.cpp b/src/images/SkImageDecoder_libpng.cpp
index 7911a293f6..9fe5fb9c95 100644
--- a/src/images/SkImageDecoder_libpng.cpp
+++ b/src/images/SkImageDecoder_libpng.cpp
@@ -141,6 +141,7 @@ static void sk_seek_fn(png_structp png_ptr, png_uint_32 offset) {
 }
 #endif
 
+#ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED
 static int sk_read_user_chunk(png_structp png_ptr, png_unknown_chunkp chunk) {
     SkImageDecoder::Peeker* peeker =
                     (SkImageDecoder::Peeker*)png_get_user_chunk_ptr(png_ptr);
@@ -148,6 +149,7 @@ static int sk_read_user_chunk(png_structp png_ptr, png_unknown_chunkp chunk) {
     return peeker->peek((const char*)chunk->name, chunk->data, chunk->size) ?
             1 : -1;
 }
+#endif
 
 static void sk_error_fn(png_structp png_ptr, png_const_charp msg) {
     SkDEBUGF(("------ png error %s\n", msg));
@@ -266,12 +268,13 @@ bool SkPNGImageDecoder::onDecodeInit(SkStream* sk_stream, png_structp *png_ptrp,
     /* If we have already read some of the signature */
 //  png_set_sig_bytes(png_ptr, 0 /* sig_read */ );
 
+#ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED
     // hookup our peeker so we can see any user-chunks the caller may be interested in
     png_set_keep_unknown_chunks(png_ptr, PNG_HANDLE_CHUNK_ALWAYS, (png_byte*)"", 0);
     if (this->getPeeker()) {
         png_set_read_user_chunk_fn(png_ptr, (png_voidp)this->getPeeker(), sk_read_user_chunk);
     }
-
+#endif
     /* The call to png_read_info() gives us all of the information from the
     * PNG file before the first IDAT (image data chunk). */
     png_read_info(png_ptr, info_ptr);
@@ -284,11 +287,13 @@ bool SkPNGImageDecoder::onDecodeInit(SkStream* sk_stream, png_structp *png_ptrp,
     if (bitDepth == 16) {
         png_set_strip_16(png_ptr);
     }
+#ifdef PNG_READ_PACK_SUPPORTED
     /* Extract multiple pixels with bit depths of 1, 2, and 4 from a single
      * byte into separate bytes (useful for paletted and grayscale images). */
     if (bitDepth < 8) {
         png_set_packing(png_ptr);
     }
+#endif
     /* Expand grayscale images to the full 8 bits from 1, 2, or 4 bits/pixel */
     if (colorType == PNG_COLOR_TYPE_GRAY && bitDepth < 8) {
         png_set_expand_gray_1_2_4_to_8(png_ptr);
@@ -494,6 +499,7 @@ bool SkPNGImageDecoder::getBitmapColorType(png_structp png_ptr, png_infop info_p
     png_get_IHDR(png_ptr, info_ptr, &origWidth, &origHeight, &bitDepth,
                  &colorType, int_p_NULL, int_p_NULL, int_p_NULL);
 
+#ifdef PNG_sBIT_SUPPORTED
     // check for sBIT chunk data, in case we should disable dithering because
     // our data is not truely 8bits per component
     png_color_8p sig_bit;
@@ -509,6 +515,7 @@ bool SkPNGImageDecoder::getBitmapColorType(png_structp png_ptr, png_infop info_p
             this->setDitherImage(false);
         }
     }
+#endif
 
     if (colorType == PNG_COLOR_TYPE_PALETTE) {
         bool paletteHasAlpha = hasTransparencyInPalette(png_ptr, info_ptr);
@@ -1217,8 +1224,9 @@ bool SkPNGImageEncoder::doEncode(SkWStream* stream, const SkBitmap& bitmap,
             png_set_tRNS(png_ptr, info_ptr, trans, numTrans, NULL);
         }
     }
-
+#ifdef PNG_sBIT_SUPPORTED
     png_set_sBIT(png_ptr, info_ptr, &sig_bit);
+#endif
     png_write_info(png_ptr, info_ptr);
 
     const char* srcImage = (const char*)bitmap.getPixels();