media: Add out-of-line copy ctors for complex classes.

media/base/bitstream_buffer.h

Index: media/base/bitstream_buffer.h
diff --git a/media/base/bitstream_buffer.h b/media/base/bitstream_buffer.h
index fe3c8da358ab021da1255517688e3693a96b4b1e..9ceeaf8967bde1c62acadec476e7e967e004a722 100644
--- a/media/base/bitstream_buffer.h
+++ b/media/base/bitstream_buffer.h
@@ -28,6 +28,8 @@ class MEDIA_EXPORT BitstreamBuffer {
                   size_t size,
                   base::TimeDelta presentation_timestamp);
 
+  BitstreamBuffer(const BitstreamBuffer& other);
+
   ~BitstreamBuffer();
 
   void SetDecryptConfig(const DecryptConfig& decrypt_config);