Add unit tests for OpusAudioDecoder.

Add unit tests for OpusAudioDecoder.

[rileya (GONE FROM CHROMIUM), 2014-01-15 19:12:41]

This is initially just the tests of the Read/Stop/Reset logic from
FFmpegAudioDecoder. Any suggestions for low-hanging-fruit-ish tests that can be
added to this?

https://codereview.chromium.org/134453009/diff/30001/media/filters/opus_audio...
File media/filters/opus_audio_decoder_unittest.cc (right):

https://codereview.chromium.org/134453009/diff/30001/media/filters/opus_audio...
media/filters/opus_audio_decoder_unittest.cc:68:
base::TimeDelta::FromMicroseconds(6500));
This is ugly, but a DCHECK fails unless this matches part of the extradata...

[xhwang, 2014-01-15 20:10:30]

The test for read/reset/stop won't be super interesting in the future when we
change read to decode and implement some SyncAudioDecoder. Can we test some real
Opus file decoding?

https://codereview.chromium.org/134453009/diff/30001/media/filters/opus_audio...
File media/filters/opus_audio_decoder_unittest.cc (right):

https://codereview.chromium.org/134453009/diff/30001/media/filters/opus_audio...
media/filters/opus_audio_decoder_unittest.cc:33: static const unsigned char
kOpusExtraData[] = {
Add a comment why we need it for this test.

global const is by default static. no need to specify "static" here.

s/unsigned char/uint8/

https://codereview.chromium.org/134453009/diff/30001/media/filters/opus_audio...
media/filters/opus_audio_decoder_unittest.cc:68:
base::TimeDelta::FromMicroseconds(6500));
On 2014/01/15 19:12:41, rileya wrote:
> This is ugly, but a DCHECK fails unless this matches part of the extradata...

Put 6500 in a constant which is defined together with kOpusExtraData, then put a
comment there explaining what's going on and why we need this.

[DaleCurtis, 2014-01-15 20:55:40]

Some nits, but otherwise lgtm

https://codereview.chromium.org/134453009/diff/30001/media/filters/opus_audio...
File media/filters/opus_audio_decoder_unittest.cc (right):

https://codereview.chromium.org/134453009/diff/30001/media/filters/opus_audio...
media/filters/opus_audio_decoder_unittest.cc:45: // Just push in an EOS buffer.
Seems like the only test which uses this is Initialize. Just move the push NULL
from all other tests here and put clear + EOS in Initialize?

https://codereview.chromium.org/134453009/diff/30001/media/filters/opus_audio...
media/filters/opus_audio_decoder_unittest.cc:56: void Initialize() {
Collapse this into the constructor, no need for a second method.

[DaleCurtis, 2014-04-25 16:59:36]

Mind if I steal this for https://codereview.chromium.org/257563007/ ?