Add speech flag to EncodedInfo

The flag indicates if the encoded bitstream is speech or comfort noise.

COAUTHOR=kwiberg@webrtc.org
R=jmarusic@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/42629004

Cr-Commit-Position: refs/heads/master@{#8598}
git-svn-id: http://webrtc.googlecode.com/svn/trunk@8598 4adac7df-926f-26a2-2b94-8c16560cd09d

webrtc/modules/audio_coding/codecs/red/audio_encoder_copy_red.cc

@@ -88,6 +88,7 @@ void AudioEncoderCopyRed::EncodeInternal(uint32_t rtp_timestamp,
     CHECK(secondary_encoded_);
     memcpy(secondary_encoded_.get(), encoded, info->encoded_bytes);
     secondary_info_ = *info;
+    DCHECK_EQ(info->speech, info->redundant[0].speech);
   }
   // Update main EncodedInfo.
   info->payload_type = red_payload_type_;