Check libpng version before reading color space

src/codec/SkPngCodec.cpp

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkCodecPriv.h"
 #include "SkColorPriv.h"
 #include "SkColorTable.h"
@@ skipping 160 matching lines @@
     // do the conversion ourselves rather than convert
     // fixed point -> double -> float.
     return ((float) x) * 0.00001f;
 }
 
 // Returns a colorSpace object that represents any color space information in
 // the encoded data.  If the encoded data contains no color space, this will
 // return NULL.
 SkColorSpace* read_color_space(png_structp png_ptr, png_infop info_ptr) {
 
+#if (PNG_LIBPNG_VER_MAJOR > 1) || (PNG_LIBPNG_VER_MAJOR == 1 && PNG_LIBPNG_VER_MINOR >= 6)
+
     // First check for an ICC profile
     png_bytep profile;
     png_uint_32 length;
     // The below variables are unused, however, we need to pass them in anyway or
     // png_get_iCCP() will return nothing.
     // Could knowing the |name| of the profile ever be interesting?  Maybe for debugging?
     png_charp name;
     // The |compression| is uninteresting since:
     //   (1) libpng has already decompressed the profile for us.
     //   (2) "deflate" is the only mode of decompression that libpng supports.
@@ skipping 51 matching lines @@
         // FIXME (msarett): Should SkFloat3x3 have a method to set the identity matrix?
         memset(toXYZD50.fMat, 0, 9 * sizeof(float));
         toXYZD50.fMat[0] = toXYZD50.fMat[4] = toXYZD50.fMat[8] = 1.0f;
 
         // Set the gammas.
         gammas.fVec[0] = gammas.fVec[1] = gammas.fVec[2] = png_fixed_point_to_float(gamma);
 
         return SkColorSpace::NewRGB(toXYZD50, gammas);
     }
 
+#endif // LIBPNG >= 1.6
+
     // Finally, what should we do if there is no color space information in the PNG?
     // The specification says that this indicates "gamma is unknown" and that the
     // "color is device dependent".  I'm assuming we can represent this with NULL.
     // But should we guess sRGB?  Most images are sRGB, even if they don't specify.
     return nullptr;
 }
 
 // Reads the header and initializes the output fields, if not NULL.
 //
 // @param stream Input data. Will be read to get enough information to properly
@@ skipping 575 matching lines @@
 
     if (1 == numberPasses) {
         return new SkPngScanlineDecoder(imageInfo, streamDeleter.detach(), chunkReader,
                                         png_ptr, info_ptr, bitDepth, colorSpace);
     }
 
     return new SkPngInterlacedScanlineDecoder(imageInfo, streamDeleter.detach(), chunkReader,
                                               png_ptr, info_ptr, bitDepth, numberPasses,
                                               colorSpace);
 }