Web MIDI: add dynamic MidiManager instantiation support for Linux

media/midi/midi_manager_win.h

 // Copyright 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 MEDIA_MIDI_MIDI_MANAGER_WIN_H_
 #define MEDIA_MIDI_MIDI_MANAGER_WIN_H_
 
 #include <stdint.h>
 
 #include <memory>
 #include <vector>
 
 #include "base/macros.h"
 #include "base/threading/thread.h"
 #include "base/time/time.h"
 #include "media/midi/midi_manager.h"
 #include "media/midi/midi_service.mojom.h"
 
 namespace midi {
 
+class MidiService;
+
 class MidiServiceWinDelegate {
  public:
   virtual ~MidiServiceWinDelegate() {}
   virtual void OnCompleteInitialization(mojom::Result result) = 0;
   virtual void OnAddInputPort(MidiPortInfo info) = 0;
   virtual void OnAddOutputPort(MidiPortInfo info) = 0;
   virtual void OnSetInputPortState(uint32_t port_index,
                                    mojom::PortState state) = 0;
   virtual void OnSetOutputPortState(uint32_t port_index,
                                     mojom::PortState state) = 0;
   virtual void OnReceiveMidiData(uint32_t port_index,
                                  const std::vector<uint8_t>& data,
                                  base::TimeTicks time) = 0;
 };
 
 class MidiServiceWin {
  public:
   virtual ~MidiServiceWin() {}
   // This method may return before the initialization is completed.
   virtual void InitializeAsync(MidiServiceWinDelegate* delegate) = 0;
   // This method may return before the specified data is actually sent.
   virtual void SendMidiDataAsync(uint32_t port_number,
                                  const std::vector<uint8_t>& data,
                                  base::TimeTicks time) = 0;
 };
 
 class MidiManagerWin final : public MidiManager, public MidiServiceWinDelegate {
  public:
-  MidiManagerWin();
+  explicit MidiManagerWin(MidiService* service);
   ~MidiManagerWin() override;
 
   // MidiManager overrides:
   void StartInitialization() final;
   void Finalize() final;
   void DispatchSendMidiData(MidiManagerClient* client,
                             uint32_t port_index,
                             const std::vector<uint8_t>& data,
                             double timestamp) final;
 
   // MidiServiceWinDelegate overrides:
   void OnCompleteInitialization(mojom::Result result) final;
   void OnAddInputPort(MidiPortInfo info) final;
   void OnAddOutputPort(MidiPortInfo info) final;
   void OnSetInputPortState(uint32_t port_index, mojom::PortState state) final;
   void OnSetOutputPortState(uint32_t port_index, mojom::PortState state) final;
   void OnReceiveMidiData(uint32_t port_index,
                          const std::vector<uint8_t>& data,
                          base::TimeTicks time) final;
 
  private:
   std::unique_ptr<MidiServiceWin> midi_service_;
   DISALLOW_COPY_AND_ASSIGN(MidiManagerWin);
 };
 
 }  // namespace midi
 
 #endif  // MEDIA_MIDI_MIDI_MANAGER_WIN_H_