Adds routed interface support between RenderFrameHost and RenderFrame

content/common/associated_interfaces.mojom

+// Copyright 2016 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.
+
+module content.mojom;
+
+// A generic, nominal interface to support transitional Channel-associated
+// interfaces at or above the content layer.
+interface AssociatedInterface {};
+
+// Analogous to the generic InterfaceProvider interface, but for content
+// AssociatedInterfaces.
+interface AssociatedInterfaceProvider {
+  GetAssociatedInterface(string name, associated AssociatedInterface& request);
+};
+
+// Implemented by anything which manages one or more routes, to map a routing
+// ID to an AssociatedInterfaceProvider.
+interface RouteProvider {
+  GetRoute(int32 routing_id, associated AssociatedInterfaceProvider& request);
+};