Revert 207992: This looks like a reland of r207983, which was reverted in

trunk/src/content/browser/renderer_host/media/midi_host.h

-// Copyright (c) 2013 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_BROWSER_RENDERER_HOST_MEDIA_MIDI_HOST_H_
-#define CONTENT_BROWSER_RENDERER_HOST_MEDIA_MIDI_HOST_H_
-
-#include "base/memory/ref_counted.h"
-#include "base/memory/scoped_ptr.h"
-#include "content/common/content_export.h"
-#include "content/public/browser/browser_message_filter.h"
-#include "content/public/browser/browser_thread.h"
-#include "media/midi/midi_manager.h"
-
-namespace media {
-class MIDIManager;
-}
-
-namespace content {
-
-class CONTENT_EXPORT MIDIHost
-    : public BrowserMessageFilter,
-      public media::MIDIManagerClient {
- public:
-  // Called from UI thread from the owner of this object.
-  MIDIHost(media::MIDIManager* midi_manager);
-
-  // BrowserMessageFilter implementation.
-  virtual void OnChannelClosing() OVERRIDE;
-  virtual void OnDestruct() const OVERRIDE;
-  virtual bool OnMessageReceived(const IPC::Message& message,
-                                 bool* message_was_ok) OVERRIDE;
-
-  // MIDIManagerClient implementation.
-  virtual void ReceiveMIDIData(
-      int port_index,
-      const uint8* data,
-      size_t length,
-      double timestamp) OVERRIDE;
-
-  // Request access to MIDI hardware.
-  void OnRequestAccess(int client_id, int access);
-
-  // Data to be sent to a MIDI output port.
-  void OnSendData(int port,
-                  const std::vector<uint8>& data,
-                  double timestamp);
-
- private:
-  friend class base::DeleteHelper<MIDIHost>;
-  friend class BrowserThread;
-
-  virtual ~MIDIHost();
-
-  media::MIDIManager* const midi_manager_;
-
-  DISALLOW_COPY_AND_ASSIGN(MIDIHost);
-};
-
-}  // namespace content
-
-#endif  // CONTENT_BROWSER_RENDERER_HOST_MEDIA_MIDI_HOST_H_