Wire up codec_delay() to MP3StreamParser and FFmpegAudioDecoder.

media/filters/ffmpeg_audio_decoder.cc

Index: media/filters/ffmpeg_audio_decoder.cc
diff --git a/media/filters/ffmpeg_audio_decoder.cc b/media/filters/ffmpeg_audio_decoder.cc
index 45f8dd4863d6da11db8b4792ee5dba86c4551948..d55e0082407bd9bcbe824de4f40e247ac2c41108 100644
--- a/media/filters/ffmpeg_audio_decoder.cc
+++ b/media/filters/ffmpeg_audio_decoder.cc
@@ -125,6 +125,10 @@ static int GetAudioBuffer(struct AVCodecContext* s, AVFrame* frame, int flags) {
   return 0;
 }
 
+static int TimeDeltaToFrames(base::TimeDelta duration, int sample_rate) {
+  return 0.5 + duration.InSecondsF() * sample_rate;
+}
+
 FFmpegAudioDecoder::FFmpegAudioDecoder(
     const scoped_refptr<base::SingleThreadTaskRunner>& task_runner)
     : task_runner_(task_runner),
@@ -267,8 +271,8 @@ void FFmpegAudioDecoder::DecodeBuffer(
         buffer->timestamp() < base::TimeDelta()) {
       // Dropping frames for negative timestamps as outlined in section A.2
       // in the Vorbis spec. http://xiph.org/vorbis/doc/Vorbis_I_spec.html
-      output_frames_to_drop_ = floor(0.5 + -buffer->timestamp().InSecondsF() *
-                                               config_.samples_per_second());
+      output_frames_to_drop_ =
+          TimeDeltaToFrames(-buffer->timestamp(), config_.samples_per_second());
     } else {
       if (last_input_timestamp_ != kNoTimestamp() &&
           buffer->timestamp() < last_input_timestamp_) {
@@ -358,10 +362,10 @@ bool FFmpegAudioDecoder::FFmpegDecode(
     if (output_timestamp_helper_->base_timestamp() == kNoTimestamp() &&
         !buffer->end_of_stream()) {
       DCHECK(buffer->timestamp() != kNoTimestamp());
-      if (output_frames_to_drop_ > 0) {
-        // Currently Vorbis is the only codec that causes us to drop samples.
-        // If we have to drop samples it always means the timeline starts at 0.
-        DCHECK_EQ(codec_context_->codec_id, AV_CODEC_ID_VORBIS);
+      if (output_frames_to_drop_ > 0 &&
+          codec_context_->codec_id == AV_CODEC_ID_VORBIS) {
+        // If we are dropping samples for Vorbis, it always means the timeline
+        // starts at 0.
         output_timestamp_helper_->SetBaseTimestamp(base::TimeDelta());
       } else {
         output_timestamp_helper_->SetBaseTimestamp(buffer->timestamp());
@@ -496,6 +500,12 @@ bool FFmpegAudioDecoder::ConfigureDecoder() {
     state_ = kUninitialized;
     return false;
   }
+
+  if (config_.codec_delay() > base::TimeDelta()) {
+    output_frames_to_drop_ =
+        TimeDeltaToFrames(config_.codec_delay(), config_.samples_per_second());
+  }
+
   return true;
 }