Python bindings: Add helper function to create InterfaceRequest

R=etiennej@chromium.org

Review URL: https://codereview.chromium.org/917923003

mojo/public/python/mojo_bindings/reflection.py

diff --git a/mojo/public/python/mojo_bindings/reflection.py b/mojo/public/python/mojo_bindings/reflection.py
index 35b8ff2..c9e4ee0 100644
--- a/mojo/public/python/mojo_bindings/reflection.py
+++ b/mojo/public/python/mojo_bindings/reflection.py
@@ -12,6 +12,7 @@
 import mojo_bindings.messaging as messaging
 import mojo_bindings.promise as promise
 import mojo_bindings.serialization as serialization
+import mojo_system
 
 
 class MojoEnumType(type):
@@ -273,6 +274,10 @@
 
     router.Start()
 
+  def NewRequest(self):
+    pipe = mojo_system.MessagePipe()
+    return (self.Proxy(pipe.handle0), InterfaceRequest(pipe.handle1))
+
   def _InternalProxy(self, router, error_handler):
     if error_handler is None:
       error_handler = _ProxyErrorHandler()