Mojo C++ Bindings: Extract AssociatedGroupController from MultiplexRouter

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

-// 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.
-
-#ifndef MOJO_PUBLIC_CPP_BINDINGS_LIB_INTERFACE_ENDPOINT_CONTROLLER_H_
-#define MOJO_PUBLIC_CPP_BINDINGS_LIB_INTERFACE_ENDPOINT_CONTROLLER_H_
-
-namespace mojo {
-
-class Message;
-
-namespace internal {
-
-// A control interface exposed by MultiplexRouter for interface endpoints.
-class InterfaceEndpointController {
- public:
-  virtual ~InterfaceEndpointController() {}
-
-  virtual bool SendMessage(Message* message) = 0;
-
-  // Allows the interface endpoint to watch for incoming sync messages while
-  // others perform sync handle watching on the same thread. Please see comments
-  // of SyncHandleWatcher::AllowWokenUpBySyncWatchOnSameThread().
-  virtual void AllowWokenUpBySyncWatchOnSameThread() = 0;
-
-  // Watches the interface endpoint for incoming sync messages. (It also watches
-  // other other handles registered to be watched together.)
-  // This method:
-  //   - returns true when |should_stop| is set to true;
-  //   - return false otherwise, including
-  //     MultiplexRouter::DetachEndpointClient() being called for the same
-  //     interface endpoint.
-  virtual bool SyncWatch(const bool* should_stop) = 0;
-};
-
-}  // namespace internal
-}  // namespace mojo
-
-#endif  // MOJO_PUBLIC_CPP_BINDINGS_LIB_INTERFACE_ENDPOINT_CONTROLLER_H_