Use ParamTraits for media::BitstreamBuffer.

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..217be7610e4684dd259918d90f20217879c3d26d 100644
--- a/media/base/bitstream_buffer.h
+++ b/media/base/bitstream_buffer.h
@@ -11,6 +11,7 @@
 #include "base/macros.h"
 #include "base/memory/shared_memory.h"
 #include "base/time/time.h"
+#include "ipc/ipc_param_traits.h"
 #include "media/base/decrypt_config.h"
 #include "media/base/media_export.h"
 #include "media/base/timestamp_constants.h"
@@ -21,6 +22,8 @@ namespace media {
 // data.  This is the media-namespace equivalent of PP_VideoBitstreamBuffer_Dev.
 class MEDIA_EXPORT BitstreamBuffer {
  public:
+  BitstreamBuffer();
+
   BitstreamBuffer(int32_t id, base::SharedMemoryHandle handle, size_t size);
 
   BitstreamBuffer(int32_t id,
@@ -36,6 +39,8 @@ class MEDIA_EXPORT BitstreamBuffer {
   base::SharedMemoryHandle handle() const { return handle_; }
   size_t size() const { return size_; }
 
+  void set_handle(const base::SharedMemoryHandle& handle) { handle_ = handle; }
+
   // The timestamp is only valid if it's not equal to |media::kNoTimestamp()|.
   base::TimeDelta presentation_timestamp() const {
     return presentation_timestamp_;
@@ -65,6 +70,8 @@ class MEDIA_EXPORT BitstreamBuffer {
   std::string iv_;                          // initialization vector
   std::vector<SubsampleEntry> subsamples_;  // clear/cypher sizes
 
+  friend struct IPC::ParamTraits<media::BitstreamBuffer>;
+
   // Allow compiler-generated copy & assign constructors.
 };