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 78910)
+++ ppapi/cpp/instance.h	(working copy)
@@ -72,6 +72,9 @@
   /** See PPP_Instance.GetInstanceObject. */
   virtual Var GetInstanceObject();
 
+  /** See PPP_Messaging.HandleMessage. */
+  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);
   // @}
 
   /**