Revert of Deletes mojo::Callback

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

 // Copyright 2015 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_MULTIPLEX_ROUTER_H_
 #define MOJO_PUBLIC_CPP_BINDINGS_LIB_MULTIPLEX_ROUTER_H_
 
 #include <stdint.h>
 
 #include <deque>
 #include <map>
 #include <memory>
 #include <string>
 
 #include "base/logging.h"
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/ref_counted_delete_on_message_loop.h"
 #include "base/memory/weak_ptr.h"
 #include "base/single_thread_task_runner.h"
 #include "base/synchronization/lock.h"
 #include "base/threading/thread_checker.h"
+#include "mojo/public/cpp/bindings/callback.h"
 #include "mojo/public/cpp/bindings/lib/connector.h"
 #include "mojo/public/cpp/bindings/lib/interface_id.h"
 #include "mojo/public/cpp/bindings/lib/message_header_validator.h"
 #include "mojo/public/cpp/bindings/lib/pipe_control_message_handler.h"
 #include "mojo/public/cpp/bindings/lib/pipe_control_message_handler_delegate.h"
 #include "mojo/public/cpp/bindings/lib/pipe_control_message_proxy.h"
 #include "mojo/public/cpp/bindings/scoped_interface_endpoint_handle.h"
 
 namespace base {
 class SingleThreadTaskRunner;
@@ skipping 226 matching lines @@
 
   bool testing_mode_;
 
   DISALLOW_COPY_AND_ASSIGN(MultiplexRouter);
 };
 
 }  // namespace internal
 }  // namespace mojo
 
 #endif  // MOJO_PUBLIC_CPP_BINDINGS_LIB_MULTIPLEX_ROUTER_H_