gpu: Remove some ipc code no longer used.

content/common/establish_channel_params.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 CONTENT_COMMON_ESTABLISH_CHANNEL_PARAMS_H_
-#define CONTENT_COMMON_ESTABLISH_CHANNEL_PARAMS_H_
-
-#include <stdint.h>
-
-#include "content/common/content_export.h"
-
-namespace content {
-
-struct CONTENT_EXPORT EstablishChannelParams {
-  EstablishChannelParams();
-  ~EstablishChannelParams();
-
-  int client_id;
-  uint64_t client_tracing_id;
-  bool preempts;
-  bool allow_view_command_buffers;
-  bool allow_real_time_streams;
-};
-
-}  // namespace content
-
-#endif  // CONTENT_COMMON_ESTABLISH_CHANNEL_PARAMS_H_