Update SourceBufferStream and its unit tests to always expect valid durations.

Update SourceBufferStream and its unit tests to always expect valid durations.

This change fixes the SourceBufferStream unit tests so that they always
provide valid durations for buffers that it passes to SourceBufferStream.
I've also added code to SoureBufferStream to verify that it always gets
buffers with valid durations.

Minor tweaks to test expectations were needed to compensate for the
SourceBufferStream behaving differently when it got actual durations instead
of using the durations it made up. In most cases I just used the duration
the SourceBufferStream was ultimately using. In a few cases the duration
the SourceBufferStream was generating didn't make any sense so I simply
changed the expectations to match the new behavior.

This is an attempt to reland https://codereview.chromium.org/379693002/ with
appropriate crash fixes.

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=283754

[acolwell GONE FROM CHROMIUM, 2014-07-16 18:17:46]

https://codereview.chromium.org/393403002/diff/20001/media/filters/ffmpeg_dem...
File media/filters/ffmpeg_demuxer.cc (right):

https://codereview.chromium.org/393403002/diff/20001/media/filters/ffmpeg_dem...
media/filters/ffmpeg_demuxer.cc:285: DVLOG(1) << "FFmpeg returned a buffer with
a negative duration! "
Filed https://code.google.com/p/chromium/issues/detail?id=394418 to track down
why FFmpeg is doing this.

[wolenetz, 2014-07-16 19:51:03]

lgtm % nit

https://codereview.chromium.org/393403002/diff/20001/media/filters/ffmpeg_dem...
File media/filters/ffmpeg_demuxer.cc (right):

https://codereview.chromium.org/393403002/diff/20001/media/filters/ffmpeg_dem...
media/filters/ffmpeg_demuxer.cc:285: DVLOG(1) << "FFmpeg returned a buffer with
a negative duration! "
On 2014/07/16 18:17:46, acolwell wrote:
> Filed https://code.google.com/p/chromium/issues/detail?id=394418 to track down
> why FFmpeg is doing this.

nit: That bug is irksome. Please add a TODO(wolenetz) here referencing that bug;
I think I'll take a look at this during some upcoming ffmpeg work.

[acolwell GONE FROM CHROMIUM, 2014-07-16 19:54:55]

https://codereview.chromium.org/393403002/diff/20001/media/filters/ffmpeg_dem...
File media/filters/ffmpeg_demuxer.cc (right):

https://codereview.chromium.org/393403002/diff/20001/media/filters/ffmpeg_dem...
media/filters/ffmpeg_demuxer.cc:285: DVLOG(1) << "FFmpeg returned a buffer with
a negative duration! "
On 2014/07/16 19:51:03, wolenetz wrote:
> On 2014/07/16 18:17:46, acolwell wrote:
> > Filed https://code.google.com/p/chromium/issues/detail?id=394418 to track
down
> > why FFmpeg is doing this.
> 
> nit: That bug is irksome. Please add a TODO(wolenetz) here referencing that
bug;
> I think I'll take a look at this during some upcoming ffmpeg work.

Done.

[acolwell GONE FROM CHROMIUM, 2014-07-16 19:54:58]

The CQ bit was checked by acolwell@chromium.org

[commit-bot: I haz the power, 2014-07-16 19:57:55]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/acolwell@chromium.org/393403002/40001

[commit-bot: I haz the power, 2014-07-17 11:25:00]

Change committed as 283754