Support (E)AC3 passthrough

media/base/audio_buffer.cc

Index: media/base/audio_buffer.cc
diff --git a/media/base/audio_buffer.cc b/media/base/audio_buffer.cc
index d563539ba07aac679662baba47b49db456208f8f..f77c2180c4b7c63624081aa7300605eacbf76e70 100644
--- a/media/base/audio_buffer.cc
+++ b/media/base/audio_buffer.cc
@@ -245,9 +245,17 @@ void AudioBuffer::ReadFrames(int frames_to_copy,
   DCHECK_EQ(dest->channels(), channel_count_);
   DCHECK_LE(source_frame_offset + frames_to_copy, adjusted_frame_count_);
 
+  dest->set_is_bitstream_format(IsBitstreamFormat());

[DaleCurtis, 2017/06/15 21:46:32]

Move into l.251 as set_is_bitstream_format(true);

[AndyWu, 2017/08/02 01:43:40]

Not really sure it's a good idea to assume the state of the parameter |dest|. I
would rather to ensure the state consistency.

+
   if (IsBitstreamFormat()) {
-    // TODO(tsunghung): Implement it along with AudioBus changes.
-    NOTREACHED() << "Invalid sample format!";
+    DCHECK(!source_frame_offset);
+    uint8_t* dest_data =
+        reinterpret_cast<uint8_t*>(dest->channel(0)) + dest->data_size();
+
+    memcpy(dest_data, channel_data_[0], data_size());
+    dest->set_data_size(dest_frame_offset + data_size());
+    dest->set_frames(dest->frames() + frame_count());
+    return;
   }
 
   DCHECK_LE(dest_frame_offset + frames_to_copy, dest->frames());