[mojo] Add GenericInterface_ to interface class variants

mojo/public/cpp/bindings/interface_request.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef MOJO_PUBLIC_CPP_BINDINGS_INTERFACE_REQUEST_H_
 #define MOJO_PUBLIC_CPP_BINDINGS_INTERFACE_REQUEST_H_
 
 #include "mojo/public/cpp/bindings/interface_ptr.h"
 
 namespace mojo {
@@ skipping 89 matching lines @@
 //
 // The client would have code similar to the following:
 //
 //   CollectorPtr collector = ...;  // Connect to Collector.
 //   SourcePtr source;
 //   InterfaceRequest<Source> source_request = GetProxy(&source);
 //   collector->RegisterSource(source.Pass());
 //   CreateSource(source_request.Pass());  // Create implementation locally.
 //
 template <typename Interface>
-InterfaceRequest<Interface> GetProxy(InterfacePtr<Interface>* ptr) {
+InterfaceRequest<typename Interface::GenericInterface>
+GetProxy(InterfacePtr<Interface>* ptr) {
   MessagePipe pipe;
-  ptr->Bind(InterfacePtrInfo<Interface>(pipe.handle0.Pass(), 0u));
-  return MakeRequest<Interface>(pipe.handle1.Pass());
+  ptr->Bind(InterfacePtrInfo<typename Interface::GenericInterface>(
+      pipe.handle0.Pass(), 0u));
+  return MakeRequest<typename Interface::GenericInterface>(
+      pipe.handle1.Pass());
 }
 
 }  // namespace mojo
 
 #endif  // MOJO_PUBLIC_CPP_BINDINGS_INTERFACE_REQUEST_H_