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 714444c9d7dfa3b20ddf48a3d71e107b5d0d3417..1ea15dd72456fb28dd30fba465cb44aef071c03f 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.
   virtual void CompleteStartSession(media::MidiResult result) override;
+  virtual void AddInputPort(const media::MidiPortInfo& info) override;
+  virtual void AddOutputPort(const media::MidiPortInfo& info) override;
   virtual 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_;