Clean up after longjmp in SkImageDecoder_libpng.

In onDecodeInit, if longjmp sends us back to setjmp, destroy the
png_struct and info_ptr before returning false. Since the
PNGAutoClean has not been created yet, we were previously
leaking resources.

R=djsollen@google.com

Review URL: https://codereview.chromium.org/68453006

git-svn-id: http://skia.googlecode.com/svn/trunk/src@12244 2bbb7eff-a529-9590-31e7-b0007b416f81
1 file changed