MediaSourceDelegate: Fix DecryptingDemuxerStream initialization logic.

MediaSourceDelegate: Fix DecryptingDemuxerStream initialization logic.

Different CDMs are supported differently. For CDMs that support a Decryptor, we'll try to use DecryptingDemuxerStream in the render side. Otherwise, we'll try to use the CDMs in the browser side. Therefore, if DecryptingDemuxerStream initialization failed, it's still possible that we can handle the audio with a CDM in the browser. Declare demuxer ready now to try that path. Note there's no need to try DecryptingDemuxerStream for video here since it is impossible to handle audio in the browser and handle video in the render process.

This also fixes the issue where CdmAttachedCB is fired twice with "false".

BUG=578203
TEST=No DCHECK when playing media/L3_audio_L3_video.mp4.mpd.

Review URL: https://codereview.chromium.org/1613793002

Cr-Commit-Position: refs/heads/master@{#372842}
(cherry picked from commit e261467104d141089906fd02e1230306cb8d0040)

Committed: https://chromium.googlesource.com/chromium/src/+/3f1b97b0b74f2540704caba24943b681fd6aaa2f

[xhwang, 2016-02-02 06:20:29]

Description was changed from

==========
MediaSourceDelegate: Fix DecryptingDemuxerStream initialization logic.

Different CDMs are supported differently. For CDMs that support a Decryptor,
we'll try to use DecryptingDemuxerStream in the render side. Otherwise, we'll
try to use the CDMs in the browser side. Therefore, if DecryptingDemuxerStream
initialization failed, it's still possible that we can handle the audio with a
CDM in the browser. Declare demuxer ready now to try that path. Note there's no
need to try DecryptingDemuxerStream for video here since it is impossible to
handle audio in the browser and handle video in the render process.

This also fixes the issue where CdmAttachedCB is fired twice with "false".

BUG=578203
TEST=No DCHECK when playing media/L3_audio_L3_video.mp4.mpd.

Review URL: https://codereview.chromium.org/1613793002

Cr-Commit-Position: refs/heads/master@{#372842}
(cherry picked from commit e261467104d141089906fd02e1230306cb8d0040)
==========

to

==========
MediaSourceDelegate: Fix DecryptingDemuxerStream initialization logic.

Different CDMs are supported differently. For CDMs that support a Decryptor,
we'll try to use DecryptingDemuxerStream in the render side. Otherwise, we'll
try to use the CDMs in the browser side. Therefore, if DecryptingDemuxerStream
initialization failed, it's still possible that we can handle the audio with a
CDM in the browser. Declare demuxer ready now to try that path. Note there's no
need to try DecryptingDemuxerStream for video here since it is impossible to
handle audio in the browser and handle video in the render process.

This also fixes the issue where CdmAttachedCB is fired twice with "false".

BUG=578203
TEST=No DCHECK when playing media/L3_audio_L3_video.mp4.mpd.

Review URL: https://codereview.chromium.org/1613793002

Cr-Commit-Position: refs/heads/master@{#372842}
(cherry picked from commit e261467104d141089906fd02e1230306cb8d0040)

Committed:
https://chromium.googlesource.com/chromium/src/+/3f1b97b0b74f2540704caba24943...
==========

[xhwang, 2016-02-02 06:20:30]

Committed patchset #1 (id:1) manually as
3f1b97b0b74f2540704caba24943b681fd6aaa2f.