A proposal and implementation for an initial postMessage interface. These in...

ppapi/cpp/instance.h

Index: ppapi/cpp/instance.h
===================================================================
--- ppapi/cpp/instance.h	(revision 78988)
+++ ppapi/cpp/instance.h	(working copy)
@@ -72,6 +72,9 @@
   /** See PPP_Instance.GetInstanceObject. */
   virtual Var GetInstanceObject();
 
+  /** See PPP_Messaging.HandleMessage. */

[polina, 2011/03/22 22:00:59]

These deserve their own section if not a separate API. Right now you are mixing
them with the Instance methods under a single sub-header comment.

[dmichael(do not use this one), 2011/03/23 17:03:18]

I moved them together with a sub-header comment.  I like having them here for
the convenience it will provide to C++.  I think a separate class will be
confusing when I later add support for MessagePorts.  In C, it's worth
separating them so we avoid changing the Instance interfaces, but we don't have
to be so concerned with API/ABI stability and backwards compatibility here.

If there's opposition, I'll cave and make a pp::Messaging class, but I think the
way I have it will be better for developers.

+  virtual void HandleMessage(const Var& message_data);
+
   /** See PPP_Instance.GetSelectedText. */
   virtual Var GetSelectedText(bool html);
   // @}
@@ -96,6 +99,9 @@
 
   /** See PPB_Instance.ExecuteScript. */
   Var ExecuteScript(const Var& script, Var* exception = NULL);
+
+  /** See PPB_Messaging.PostMessage. */
+  void PostMessage(const Var& message);
   // @}
 
   /**