libwebp: cherry-pick some demux changes

libwebp: cherry-pick some demux changes

these make the demuxer more strict when parsing files with VP8X flags that
don't match the data.

e18e667 demux: strictly enforce the animation flag
61cb884 demux: (non-exp) fail if the fragmented flag is set

BUG=317284
TBR=fbarchard

[urvang, 2013-11-15 19:57:36]

lgtm

[commit-bot: I haz the power, 2013-11-15 22:52:57]

No LGTM from a valid reviewer yet. Only full committers are accepted.
Even if an LGTM may have been provided, it was from a non-committer or
a lowly provisional committer, _not_ a full super star committer.
See http://www.chromium.org/getting-involved/become-a-committer
Note that this has nothing to do with OWNERS files.

[urvang (Google), 2013-11-18 20:04:11]

lgtm

LGTM stamp as a committer.

[commit-bot: I haz the power, 2013-11-18 20:06:38]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/jzern@chromium.org/60863004/1

[commit-bot: I haz the power, 2013-11-18 20:25:37]

Retried try job too often on chromium_presubmit for step(s) presubmit
http://build.chromium.org/p/tryserver.chromium/buildstatus?builder=chromium_p...

[commit-bot: I haz the power, 2013-11-18 20:33:43]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/jzern@chromium.org/60863004/1

[commit-bot: I haz the power, 2013-11-19 00:45:03]

Retried try job too often on win_rel for step(s) browser_tests
http://build.chromium.org/p/tryserver.chromium/buildstatus?builder=win_rel&nu...

[jzern, 2013-11-21 23:24:41]

On 2013/11/19 00:45:03, I haz the power (commit-bot) wrote:
> Retried try job too often on win_rel for step(s) browser_tests
>
http://build.chromium.org/p/tryserver.chromium/buildstatus?builder=win_rel&nu...

Urvang dcommit'd this change:

commit 7bd6087219d6f8de0d5ab8c5b801ff7f4f5abfd6
Author: urvang@google.com
<urvang@google.com@0039d316-1c4b-4281-b951-d872f2087c98>
Date:   Tue Nov 19 01:13:57 2013 +0000

    libwebp: cherry-pick some demux changes
    
    these make the demuxer more strict when parsing files with VP8X flags that
    don't match the data.
    
    e18e667 demux: strictly enforce the animation flag
    61cb884 demux: (non-exp) fail if the fragmented flag is set
    
    BUG=317284
    R=urvang@google.com
    TBR=fbarchard
    
    Review URL: https://codereview.chromium.org/60863004
    
    git-svn-id: svn://svn.chromium.org/chrome/trunk/src@235867
0039d316-1c4b-4281-b951-d872f2087c98

[fbarchard, 2013-11-23 01:01:56]

https://codereview.chromium.org/60863004/diff/1/third_party/libwebp/demux/dem...
File third_party/libwebp/demux/demux.c (right):

https://codereview.chromium.org/60863004/diff/1/third_party/libwebp/demux/dem...
third_party/libwebp/demux/demux.c:512: const int has_frames =
!!(dmux->feature_flags_ & ANIMATION_FLAG);
!! is obscure.  
const int has_frames = dmux->feature_flags_ & ANIMATION_FLAG;
will do, as long as you use boolean operators.  e.g. || has_frames.
or more conventional would be

(dmux->feature_flags_ & ANIMATION_FLAG) != 0;
or
(dmux->feature_flags_ & ANIMATION_FLAG) == ANIMATION_FLAG;

https://codereview.chromium.org/60863004/diff/1/third_party/libwebp/demux/dem...
third_party/libwebp/demux/demux.c:603: // TODO(jzern): this is insufficient in
the fragmented image case if the
Prefer comments start with uppercase.
This is insufficient.
Prefer a todo that indicates the action to be taken, not the problem.
A problem is best documented with a bug #.