media: Add support for playback of VP8 Alpha video streams

media/base/decoder_buffer.h

Index: media/base/decoder_buffer.h
diff --git a/media/base/decoder_buffer.h b/media/base/decoder_buffer.h
index c23e88f5fcc85820c9c322b9475955329b31711d..168ab2ca9c76d13367dafa983c35f1cf77766894 100644
--- a/media/base/decoder_buffer.h
+++ b/media/base/decoder_buffer.h
@@ -47,6 +47,13 @@ class MEDIA_EXPORT DecoderBuffer
   // padded and aligned as necessary.  |data| must not be NULL and |size| >= 0.
   static scoped_refptr<DecoderBuffer> CopyFrom(const uint8* data, int size);
 
+  // Create a DecoderBuffer whose |data_| is copied from |data| and |side_data_|
+  // is copied from |side_data|. Buffers will be padded and aligned as necessary
+  // Data pointers must not be NULL and sizes must be >= 0.
+  static scoped_refptr<DecoderBuffer> CopyFrom(const uint8* data, int size,

[scherkus (not reviewing), 2013/04/04 22:54:00]

can you add unit tests?

[vignesh, 2013/04/05 19:06:58]

Done.

+                                               const uint8* side_data,
+                                               int side_data_size);
+
   // Create a DecoderBuffer indicating we've reached end of stream.
   //
   // Calling any method other than IsEndOfStream() on the resulting buffer
@@ -64,6 +71,9 @@ class MEDIA_EXPORT DecoderBuffer
 
   int GetDataSize() const;
 
+  const uint8* GetSideData() const;
+  int GetSideDataSize() const;
+
   const DecryptConfig* GetDecryptConfig() const;
   void SetDecryptConfig(scoped_ptr<DecryptConfig> decrypt_config);
 
@@ -80,6 +90,8 @@ class MEDIA_EXPORT DecoderBuffer
   // will be padded and aligned as necessary.  If |data| is NULL then |data_| is
   // set to NULL and |buffer_size_| to 0.
   DecoderBuffer(const uint8* data, int size);

[scherkus (not reviewing), 2013/04/04 22:54:00]

given these are private constructors, I would remove this one and have existing
clients call DecodeBuffer() w/ NULL/0 side data

no need to duplicate

[vignesh, 2013/04/05 19:06:58]

This is a protected constructor, not private. I see atleast one subclass
(stream_parser_buffer.cc) that calls this constructor. So, I think it's better
off to leave it as it is, rather than going around and changing the subclasses
as well. Thoughts?

+  DecoderBuffer(const uint8* data, int size,
+                const uint8* side_data, int side_data_size);
   virtual ~DecoderBuffer();
 
  private:
@@ -88,6 +100,8 @@ class MEDIA_EXPORT DecoderBuffer
 
   int size_;
   scoped_ptr<uint8, base::ScopedPtrAlignedFree> data_;
+  int side_data_size_;
+  scoped_ptr<uint8, base::ScopedPtrAlignedFree> side_data_;
   scoped_ptr<DecryptConfig> decrypt_config_;
 
   // Constructor helper method for memory allocations.