Use the default resync_to_restart in jpeg.

Use the default resync_to_restart in jpeg.

Our version requires rewinding the stream, which is not always
supported. Instead, depend on jpeg's default version.

R=djsollen@google.com

Committed: https://code.google.com/p/skia/source/detail?r=11458

[scroggo, 2013-09-12 00:06:38]

This change is also being made in Android. Copying some comments from that code
review:

Q. What does the default jpeg implementation do?
A. According to the spec:

"jpeg_resync_to_restart() is the default resync procedure that a data source
manager can invoke when the decompressor fails to find a restart (RSTn) marker
where one is expected. The function shall find a suitable point for resuming
decompression and position the input stream to the next data segment."

If the encoded jpeg file has restart markers and there is a transmission error,
this function will allow decoding to recover. libjpeg.doc actually recommends
using the default for most applications.

jdmarker.c goes into more detail about what the default does, but it generally
skips some data (which was likely bogus) and resumes where it can. The comments
by jpeg_resync_to_restart in that file also give some direction on what an
implementation should do: find the next data segment and (usually) set
cinfo->unread_marker to zero. Our current implementation ignores the desired
param and rewinds to the very beginning, which is likely not what we want. If we
were going to override the default, we should probably be backing up only far
enough to find the correct restart marker. Since Android streams do not
necessarily support rewind and our implementation is questionable, I think it
makes more sense to stick with the default.

[djsollen, 2013-09-12 01:52:46]

lgtm

[scroggo, 2013-09-25 21:17:45]

Committed patchset #1 manually as r11458 (presubmit successful).