Mojo C++ bindings: Generate InterfaceHandle<> instead of InterfacePtr<>.

mojo/public/cpp/bindings/interface_request.h

Index: mojo/public/cpp/bindings/interface_request.h
diff --git a/mojo/public/cpp/bindings/interface_request.h b/mojo/public/cpp/bindings/interface_request.h
index 515fe88b70b9eabaac82f386dd1731be072fcac4..0d634a2cd4cadef32c3a27d8897def82652596f1 100644
--- a/mojo/public/cpp/bindings/interface_request.h
+++ b/mojo/public/cpp/bindings/interface_request.h
@@ -122,6 +122,17 @@ InterfaceRequest<Interface> GetProxy(InterfacePtr<Interface>* ptr) {
   return MakeRequest<Interface>(pipe.handle1.Pass());
 }
 
+// This is an overload of GetProxy() that assumes that the client end of the
+// handle is an InterfaceHandle<>. It creates a new message pipe over which the
+// Interface is to be served. InterfaceHandle<> represents the client's end,
+// and InterfaceRequest<> should be used to bind to an implementation.
+template <typename Interface>
+InterfaceRequest<Interface> GetProxy(InterfaceHandle<Interface>* ptr) {
+  MessagePipe pipe;
+  *ptr = InterfaceHandle<Interface>(pipe.handle0.Pass(), 0u);
+  return MakeRequest<Interface>(pipe.handle1.Pass());
+}
+
 }  // namespace mojo
 
 #endif  // MOJO_PUBLIC_CPP_BINDINGS_INTERFACE_REQUEST_H_