Use passthrough decoder for (E)AC3 formats

media/base/audio_buffer.h

Index: media/base/audio_buffer.h
diff --git a/media/base/audio_buffer.h b/media/base/audio_buffer.h
index e97e2c23fd1e129db527fea552708382cc32a3b8..c67862cfdd834f85450b86be652f90d055851c3b 100644
--- a/media/base/audio_buffer.h
+++ b/media/base/audio_buffer.h
@@ -64,6 +64,20 @@ class MEDIA_EXPORT AudioBuffer
       const base::TimeDelta timestamp,
       scoped_refptr<AudioBufferMemoryPool> pool = nullptr);
 
+  // Create an AudioBuffer for compressed bitstream. Its channel data is copied
+  // from |data|, and the size is |data_size|. |data| must not be null and
+  // |frame_count| must be >= 0.
+  static scoped_refptr<AudioBuffer> CopyBitstreamFrom(
+      SampleFormat sample_format,
+      ChannelLayout channel_layout,
+      int channel_count,
+      int sample_rate,
+      int frame_count,
+      const uint8_t* const* data,
+      const size_t data_size,
+      const base::TimeDelta timestamp,
+      scoped_refptr<AudioBufferMemoryPool> pool = nullptr);
+
   // Create an AudioBuffer with |frame_count| frames. Buffer is allocated, but
   // not initialized. Timestamp and duration are set to kNoTimestamp. For
   // optimal efficiency when many buffers are being created, a
@@ -76,6 +90,17 @@ class MEDIA_EXPORT AudioBuffer
       int frame_count,
       scoped_refptr<AudioBufferMemoryPool> pool = nullptr);
 
+  // Create an AudioBuffer for compressed bitstream. Buffer is allocated, but
+  // not initialized. Timestamp and duration are set to kNoTimestamp.
+  static scoped_refptr<AudioBuffer> CreateBitstreamBuffer(
+      SampleFormat sample_format,
+      ChannelLayout channel_layout,
+      int channel_count,
+      int sample_rate,
+      int frame_count,
+      size_t data_size,
+      scoped_refptr<AudioBufferMemoryPool> pool = nullptr);
+
   // Create an empty AudioBuffer with |frame_count| frames.
   static scoped_refptr<AudioBuffer> CreateEmptyBuffer(
       ChannelLayout channel_layout,
@@ -128,6 +153,9 @@ class MEDIA_EXPORT AudioBuffer
   // Return the sample rate.
   int sample_rate() const { return sample_rate_; }
 
+  // Return the sample format.

[DaleCurtis, 2017/05/04 19:05:44]

Can we drop this? And instead return IsBitstreamFormat()?  I don't want clients
thinking they can know the sample format for AudioBuffers, they are expected to
use Read() irrespective of the format.

[AndyWu, 2017/05/06 01:46:48]

Done, you are right, IsBitstreamFormat() is enough.

+  SampleFormat sample_format() const { return sample_format_; }
+
   // Return the channel layout.
   ChannelLayout channel_layout() const { return channel_layout_; }
 
@@ -168,6 +196,7 @@ class MEDIA_EXPORT AudioBuffer
               int frame_count,
               bool create_buffer,
               const uint8_t* const* data,
+              const size_t data_size,
               const base::TimeDelta timestamp,
               scoped_refptr<AudioBufferMemoryPool> pool);