Update to libpng 1.2.52 (rollup change only)

Update to libpng 1.2.52 (rollup change only)

Verified that both of the fixes mentioned in README.chromium were
fixed in upstream.  Upstream used a slightly different approach to
detecting whether "prefix_size + expanded_size + 1" overflows in
pngrutil.c, but their solution looks okay too.

TBR=darin@chromium.org
BUG=532758
Committed: https://crrev.com/6d08cb245c6d904a9b0ffe745ea98bb73fdd9a00
Cr-Commit-Position: refs/heads/master@{#351445}

[mdempsky, 2015-09-29 19:44:38]

mdempsky@chromium.org changed reviewers:
+ inferno@chromium.org, noel@chromium.org

[Noel Gordon, 2015-09-29 23:43:32]

Right, layout tests passing and a good sign: LayoutTests/fast/images/png-suite/*
gives us coverage, text chunk reading in the layout test image_diff tool still
works it seems, and ClusterFuzz will do examine the rest.

Chrome already had the fixes, per the bug and chromium.README, so no change in
behavior here.

LGTM.

[Noel Gordon, 2015-09-29 23:56:41]

The CQ bit was checked by noel@chromium.org

[commit-bot: I haz the power, 2015-09-29 23:58:29]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1372313004/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1372313004/1

[Noel Gordon, 2015-09-29 23:59:06]

TBR=darin for a third_party landing (daring: nothing to do here).

[commit-bot: I haz the power, 2015-09-30 00:11:43]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-09-30 00:13:12]

Patchset 1 (id:??) landed as
https://crrev.com/6d08cb245c6d904a9b0ffe745ea98bb73fdd9a00
Cr-Commit-Position: refs/heads/master@{#351445}

[Noel Gordon, 2015-09-30 00:14:03]

On 2015/09/30 00:11:43, commit-bot: I haz the power wrote:
> Committed patchset #1 (id:1)

Fascinating: CQ did not record where this patch was landed.

[Noel Gordon, 2015-09-30 00:14:47]

On 2015/09/30 00:14:03, noel gordon wrote:
> On 2015/09/30 00:11:43, commit-bot: I haz the power wrote:
> > Committed patchset #1 (id:1)
> 
> Fascinating: CQ did not record where this patch was landed.

Oh it did eventually, ignore me.

https://crrev.com/6d08cb245c6d904a9b0ffe745ea98bb73fdd9a00
Cr-Commit-Position: refs/heads/master@{#351445}

[Lei Zhang, 2015-09-30 00:24:49]

Uh, a) darin isn't actually CC'd on the bug, and b) darin isn't in
third_party/OWNERS.

[Noel Gordon, 2015-09-30 02:05:49]

On 2015/09/30 00:24:49, Lei Zhang wrote:
> Uh, a) darin isn't actually CC'd on the bug, and b) darin isn't in
> third_party/OWNERS.

So did you notice haw that does not bug him, and that he is a top-level owner?
And we have been using this procedure for years ...