ppapi: implement PPB_AudioEncoder

ppapi/shared_impl/media_stream_buffer.h

Index: ppapi/shared_impl/media_stream_buffer.h
diff --git a/ppapi/shared_impl/media_stream_buffer.h b/ppapi/shared_impl/media_stream_buffer.h
index 8b0ebe1cc40bec8f45ac007415a994e210d68634..ddb67295c346a293e62d4436bcbc98bab84415f3 100644
--- a/ppapi/shared_impl/media_stream_buffer.h
+++ b/ppapi/shared_impl/media_stream_buffer.h
@@ -11,7 +11,12 @@
 namespace ppapi {
 
 union MediaStreamBuffer {
-  enum Type { TYPE_UNKNOWN = 0, TYPE_AUDIO = 1, TYPE_VIDEO = 2, };
+  enum Type {
+    TYPE_UNKNOWN = 0,
+    TYPE_AUDIO = 1,
+    TYPE_VIDEO = 2,
+    TYPE_BITSTREAM = 3
+  };
 
   struct Header {
     Type type;
@@ -41,16 +46,26 @@ union MediaStreamBuffer {
     uint8_t data[8];
   };
 
+  struct Bitstream {
+    Header header;
+    uint32_t data_size;
+    // Uses 8 bytes to make sure the Bitstream struct has consistent size
+    // between NaCl code and renderer code.
+    uint8_t data[8];
+  };
+
   // Because these structs are written and read in shared memory, we need
   // the size and alighment to be consistent between NaCl and its host trusted
   // platform.
   PP_COMPILE_ASSERT_SIZE_IN_BYTES(Header, 8);
   PP_COMPILE_ASSERT_SIZE_IN_BYTES(Audio, 40);
   PP_COMPILE_ASSERT_SIZE_IN_BYTES(Video, 40);
+  PP_COMPILE_ASSERT_SIZE_IN_BYTES(Bitstream, 20);
 
   Header header;
   Video video;
   Audio audio;
+  Bitstream bitstream;
 };
 
 }  // namespace ppapi