Web MIDI: add blink APIs to notify device connection events

Source/modules/webmidi/MIDIOutput.h

Index: Source/modules/webmidi/MIDIOutput.h
diff --git a/Source/modules/webmidi/MIDIOutput.h b/Source/modules/webmidi/MIDIOutput.h
index 2b8d0c1930210d82c09c42374ae6338feb654fee..3b0170ee815184bc12fdd46f5d61784bf3ca4fe1 100644
--- a/Source/modules/webmidi/MIDIOutput.h
+++ b/Source/modules/webmidi/MIDIOutput.h
@@ -42,7 +42,7 @@ class MIDIAccess;
 class MIDIOutput final : public MIDIPort {
     DEFINE_WRAPPERTYPEINFO();
 public:
-    static MIDIOutput* create(MIDIAccess*, unsigned portIndex, const String& id, const String& manufacturer, const String& name, const String& version);
+    static MIDIOutput* create(MIDIAccess*, unsigned portIndex, const String& id, const String& manufacturer, const String& name, const String& version, bool isActive);
     virtual ~MIDIOutput();
 
     void send(Uint8Array*, double timestamp, ExceptionState&);
@@ -55,7 +55,7 @@ public:
     virtual void trace(Visitor*) override;
 
 private:
-    MIDIOutput(MIDIAccess*, unsigned portIndex, const String& id, const String& manufacturer, const String& name, const String& version);
+    MIDIOutput(MIDIAccess*, unsigned portIndex, const String& id, const String& manufacturer, const String& name, const String& version, bool isActive);
 
     unsigned m_portIndex;
 };