Fix unninitialized 'tmp' in CJBig2_Image::composeTo_opt2

Fix unninitialized 'tmp' in CJBig2_Image::composeTo_opt2

BUG=387811
R=tsepez@chromium.org

Committed: https://pdfium.googlesource.com/pdfium/+/06a8c87

[jun_fang, 2014-08-04 04:39:08]

please review this fix.

[Tom Sepez, 2014-08-04 17:58:22]

https://codereview.chromium.org/437483004/diff/1/core/src/fxcodec/jbig2/JBig2...
File core/src/fxcodec/jbig2/JBig2_Image.cpp (right):

https://codereview.chromium.org/437483004/diff/1/core/src/fxcodec/jbig2/JBig2...
core/src/fxcodec/jbig2/JBig2_Image.cpp:795: } else {
can we remove some of these   else { ys0 = 0 } branches if we're setting them
all to zero above?  Alternatively, can we keep the branches and figure out which
ones need to be initialized vs. which ones dont?

[palmer, 2014-08-04 18:58:41]

Does this vulnerability exist in the upstream Jbig2 code?

[jun_fang, 2014-08-04 19:10:32]

On 2014/08/04 18:58:41, Chromium Palmer wrote:
> Does this vulnerability exist in the upstream Jbig2 code?

I am not sure.

[Tom Sepez, 2014-08-05 17:22:56]

lgtm

[jun_fang, 2014-08-05 17:53:11]

Committed patchset #2 manually as r06a8c87 (presubmit successful).