Code: store_current_palette(png_store *ps, int *npalette)
{
 /* This is an internal error (the call has been made outside a read

     * operation.)
     */
    if (ps->current == NULL)
       store_log(ps, ps->pread, "no current stream for palette", 1);
 
    /* The result may be null if there is no palette. */
    *npalette = ps->current->npalette;
 return ps->current->palette;
}

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)
