Revert of ozone: gpu: Add plumbing for platform-specific gpu messaging

ui/ozone/gpu/gpu_platform_support.h

-// Copyright 2014 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 UI_OZONE_GPU_GPU_PLATFORM_SUPPORT_H_
-#define UI_OZONE_GPU_GPU_PLATFORM_SUPPORT_H_
-
-#include "ipc/ipc_listener.h"
-#include "ipc/ipc_sender.h"
-#include "ui/ozone/ozone_export.h"
-
-namespace ui {
-
-// Platform-specific object to support a GPU process.
-//
-// See GpuPlatformSupportHost for more context.
-class OZONE_EXPORT GpuPlatformSupport : public IPC::Listener {
- public:
-  GpuPlatformSupport();
-  virtual ~GpuPlatformSupport();
-
-  // Called when the GPU process is spun up & channel established.
-  virtual void OnChannelEstablished(IPC::Sender* sender) = 0;
-};
-
-// Create a stub implementation.
-OZONE_EXPORT GpuPlatformSupport* CreateStubGpuPlatformSupport();
-
-}  // namespace ui
-
-#endif  // UI_OZONE_GPU_GPU_PLATFORM_SUPPORT_H_