Stop assuming metadata contains at least one stream

Stop assuming metadata contains at least one stream

It is valid for a media::Demuxer implementation to provide 0 streams in
GetAllStreams().  In this case, the metadata built by PipelineImpl is
empty too.  This should be handled, just like PipelineImpl already
handles absence of streams with PIPELINE_ERROR_COULD_NOT_RENDER.

TEST=media_blink_unittests

Review-Url: https://codereview.chromium.org/2930333004
Cr-Commit-Position: refs/heads/master@{#479066}
Committed: https://chromium.googlesource.com/chromium/src/+/a78fa9bff9f98f927593982384e8e56cbcd0a43c

[wdzierzanowski, 2017-06-13 11:52:56]

wdzierzanowski@opera.com changed reviewers:
+ dalecurtis@chromium.org

[wdzierzanowski, 2017-06-13 11:52:56]

Hi!

This came up while implementing a new media::Demuxer. There's this small
inconsistency regarding the requirements of Initialize() vs. GetAllStreams(). A
Demuxer is allowed to Initialize() successfully even though there are no (valid)
streams, because PipelineImpl will fail with PIPELINE_ERROR_COULD_NOT_RENDER
anyway. At the same time, WebMediaPlayerImpl was assuming there is at least one
stream.

[DaleCurtis, 2017-06-13 15:47:11]

Nice catch, lgtm!

[DaleCurtis, 2017-06-13 15:47:14]

The CQ bit was checked by dalecurtis@chromium.org

[commit-bot: I haz the power, 2017-06-13 15:47:36]

CQ is trying da patch.

Follow status at:
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2017-06-13 18:12:12]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1497368834808190, "parent_rev":
"afe0e0fd03e2e3de8c49cc2b0325da1689b24d8c", "commit_rev":
"a78fa9bff9f98f927593982384e8e56cbcd0a43c"}

[commit-bot: I haz the power, 2017-06-13 18:12:27]

Description was changed from

==========
Stop assuming metadata contains at least one stream

It is valid for a media::Demuxer implementation to provide 0 streams in
GetAllStreams().  In this case, the metadata built by PipelineImpl is
empty too.  This should be handled, just like PipelineImpl already
handles absence of streams with PIPELINE_ERROR_COULD_NOT_RENDER.

TEST=media_blink_unittests
==========

to

==========
Stop assuming metadata contains at least one stream

It is valid for a media::Demuxer implementation to provide 0 streams in
GetAllStreams().  In this case, the metadata built by PipelineImpl is
empty too.  This should be handled, just like PipelineImpl already
handles absence of streams with PIPELINE_ERROR_COULD_NOT_RENDER.

TEST=media_blink_unittests

Review-Url: https://codereview.chromium.org/2930333004
Cr-Commit-Position: refs/heads/master@{#479066}
Committed:
https://chromium.googlesource.com/chromium/src/+/a78fa9bff9f98f927593982384e8...
==========

[commit-bot: I haz the power, 2017-06-13 18:12:27]

Committed patchset #1 (id:1) as
https://chromium.googlesource.com/chromium/src/+/a78fa9bff9f98f927593982384e8...