Reland: Web MIDI: split build rules for media/midi

media/midi/midi_scheduler.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 MEDIA_MIDI_MIDI_SCHEDULER_H_
 #define MEDIA_MIDI_MIDI_SCHEDULER_H_
 
 #include "base/callback.h"
 #include "base/memory/weak_ptr.h"
+#include "media/base/media_export.h"
 
 namespace media {
 
 class MidiManager;
 class MidiManagerClient;
 
 // TODO(crbug.com/467442): Make tasks cancelable per client.
-class MidiScheduler final {
+class MEDIA_EXPORT MidiScheduler final {
  public:
   explicit MidiScheduler(MidiManager* manager);
   ~MidiScheduler();
 
   // Post |closure| to the current message loop safely. The |closure| will not
   // be invoked after MidiScheduler is deleted. AccumulateMidiBytesSent() of
   // |client| is called internally.
   void PostSendDataTask(MidiManagerClient* client,
                         size_t length,
                         double timestamp,
                         const base::Closure& closure);
 
  private:
   void InvokeClosure(MidiManagerClient* client,
                      size_t length,
                      const base::Closure& closure);
 
   // MidiManager should own the MidiScheduler and be alive longer.
   MidiManager* manager_;
   base::WeakPtrFactory<MidiScheduler> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(MidiScheduler);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_MIDI_MIDI_SCHEDULER_H_