Code:  set_modifier_for_read(png_modifier *pm, png_infopp ppi, png_uint_32 id,
    PNG_CONST char *name)
 {
    /* Do this first so that the modifier fields are cleared even if an error
     * happens allocating the png_struct.  No allocation is done here so no
    * cleanup is required.
    */
   pm->state = modifier_start;
   pm->bit_depth = 0;
   pm->colour_type = 255;

   pm->pending_len = 0;
   pm->pending_chunk = 0;
   pm->flush = 0;
   pm->buffer_count = 0;
   pm->buffer_position = 0;

 return set_store_for_read(&pm->this, ppi, id, name);
}

Vulnerability Type: +Priv 
CWE ID: 
Summary: Unspecified vulnerability in libpng before 1.6.20, as used in Android 4.x before 4.4.4, 5.0.x before 5.0.2, 5.1.x before 5.1.1, and 6.x before 2016-07-01, allows attackers to gain privileges via a crafted application, as demonstrated by obtaining Signature or SignatureOrSystem access, aka internal bug 23265085.
Commit Message: DO NOT MERGE Update libpng to 1.6.20

BUG:23265085
Change-Id: I85199805636d771f3597b691b63bc0bf46084833
(cherry picked from commit bbe98b40cda082024b669fa508931042eed18f82)
