Web MIDI: distributes MIDIPort information asynchronously

content/browser/media/midi_host.h

Index: content/browser/media/midi_host.h
diff --git a/content/browser/media/midi_host.h b/content/browser/media/midi_host.h
index acaee52bb901ea546c7ad9d9dc4e0d4b53106379..3a469bf93b9e2eef4ab6a2656f7e899877e15736 100644
--- a/content/browser/media/midi_host.h
+++ b/content/browser/media/midi_host.h
@@ -37,6 +37,8 @@ class CONTENT_EXPORT MidiHost
 
   // MidiManagerClient implementation.
   void CompleteStartSession(media::MidiResult result) override;
+  void AddInputPort(const media::MidiPortInfo& info) override;
+  void AddOutputPort(const media::MidiPortInfo& info) override;
   void ReceiveMidiData(uint32 port,
                        const uint8* data,
                        size_t length,
@@ -86,6 +88,9 @@ class CONTENT_EXPORT MidiHost
   // Buffers where data sent from each MIDI input port is stored.
   ScopedVector<media::MidiMessageQueue> received_messages_queues_;
 
+  // Protects access to |received_messages_queues_|;
+  base::Lock messages_queues_lock_;
+
   // The number of bytes sent to the platform-specific MIDI sending
   // system, but not yet completed.
   size_t sent_bytes_in_flight_;