Web MIDI API back-end (work-in-progress)

content/common/media/media_param_traits.h

Index: content/common/media/media_param_traits.h
diff --git a/content/common/media/media_param_traits.h b/content/common/media/media_param_traits.h
index 90d7258604574760a75fde913a5eb963f46c3a5f..dabcc3b29cd4d4828bf948430fc9bb73c569e555 100644
--- a/content/common/media/media_param_traits.h
+++ b/content/common/media/media_param_traits.h
@@ -11,6 +11,7 @@
 
 namespace media {
 class AudioParameters;
+class MIDIPortInfoList;
 struct VideoCaptureParams;
 }
 
@@ -32,6 +33,13 @@ struct CONTENT_EXPORT ParamTraits<media::VideoCaptureParams> {
   static void Log(const param_type& p, std::string* l);
 };
 
+template <>
+struct CONTENT_EXPORT ParamTraits<media::MIDIPortInfoList> {

[scherkus (not reviewing), 2013/06/12 01:28:47]

hrm... if MIDIPortInfoList was a typedef would you still need all this stuff?

also you may want to take a look at the IPC_STRUCT_TRAITS_XXX() set of macros --
I believe they help autogenerate this kind of code

[Chris Rogers, 2013/06/12 20:34:35]

I took a look at IPC_STRUCT_TRAITS_BEGIN, IPC_STRUCT_TRAITS_MEMBER, etc. which
we use in many places, but couldn't find an example where it's a *list* of
structs that we want to send.  If you can help point me in the right direction
for how to do this for things which are vector<struct>, I'm happy to change it. 
For now, I'm not sure if it's possible, so that's why I wrote the pickling like
it is now.

[scherkus (not reviewing), 2013/06/13 02:05:41]

AFAIK the IPC system knows how to deal with std::vector so you only need to
provide a traits definition for the struct itself.

IPC_STRUCT_TRAITS_BEGIN(media::MIDIPortInfo)
  IPC_STRUCT_TRAITS_MEMBER(...)
IPC_STRUCT_TRAITS_END(media::MIDIPortInfo)

+  typedef media::MIDIPortInfoList param_type;
+  static void Write(Message* m, const param_type& p);
+  static bool Read(const Message* m, PickleIterator* iter, param_type* r);
+  static void Log(const param_type& p, std::string* l);
+};
 
 } // namespace IPC