Mojo Channel: Fix deferred proxy dispatch; support paused channels

ipc/ipc_test.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 IPC.mojom;
 
 interface SimpleTestDriver {
   ExpectValue(int32 value);
 
   [Sync]
   GetExpectedValue() => (int32 value);
 
   [Sync]
   RequestValue() => (int32 value);
 
   RequestQuit() => ();
 };
 
 interface SimpleTestClient {
   [Sync]
   RequestValue() => (int32 value);
 };
+
+interface PingReceiver {
+  Ping() => ();
+};
+
+interface IndirectTestDriver {
+  GetPingReceiver(associated PingReceiver& request);
+};