Mojo C++ bindings: introduce public associated-interface-related types.

mojo/public/cpp/bindings/lib/interface_endpoint_client.h

Index: mojo/public/cpp/bindings/lib/interface_endpoint_client.h
diff --git a/mojo/public/cpp/bindings/lib/interface_endpoint_client.h b/mojo/public/cpp/bindings/lib/interface_endpoint_client.h
index b3f3f5a6069e3cf8fc74da83c912c8781f8f8a64..260fd3bb79355e0c46678a87df9c16dccacc1e71 100644
--- a/mojo/public/cpp/bindings/lib/interface_endpoint_client.h
+++ b/mojo/public/cpp/bindings/lib/interface_endpoint_client.h
@@ -18,8 +18,13 @@
 #include "mojo/public/cpp/bindings/message_filter.h"
 
 namespace mojo {
+
+class AssociatedGroup;
+
 namespace internal {
 
+class MultiplexRouter;
+
 // InterfaceEndpointClient handles message sending and receiving of an interface
 // endpoint, either the implementation side or the client side.
 // It should only be accessed and destructed on the creating thread.
@@ -52,6 +57,7 @@ class InterfaceEndpointClient : public MessageReceiverWithResponder {
   }
 
   MultiplexRouter* router() const { return handle_.router(); }
+  AssociatedGroup* associated_group();
 
   // After this call the object is in an invalid state and shouldn't be reused.
   ScopedInterfaceEndpointHandle PassHandle();
@@ -94,6 +100,7 @@ class InterfaceEndpointClient : public MessageReceiverWithResponder {
   bool HandleValidatedMessage(Message* message);
 
   ScopedInterfaceEndpointHandle handle_;
+  scoped_ptr<AssociatedGroup> associated_group_;
 
   MessageReceiverWithResponderStatus* const incoming_receiver_;
   scoped_ptr<MessageFilter> payload_validator_;