Web MIDI: implement implicit open() on send() and setOnmidimessage()

Source/modules/webmidi/MIDIPort.h

Index: Source/modules/webmidi/MIDIPort.h
diff --git a/Source/modules/webmidi/MIDIPort.h b/Source/modules/webmidi/MIDIPort.h
index 12babafdc56aaab9827cad35a03cd99d89fe24f5..755516f3ec5f6173912a109df907c486393b7f5d 100644
--- a/Source/modules/webmidi/MIDIPort.h
+++ b/Source/modules/webmidi/MIDIPort.h
@@ -66,6 +66,7 @@ public:
     MIDIAccess* midiAccess() const { return m_access; }
     MIDIAccessor::MIDIPortState getState() const { return m_state; }
     void setState(MIDIAccessor::MIDIPortState);
+    ConnectionState getConnection() const { return m_connection; }
 
     DECLARE_VIRTUAL_TRACE();
 
@@ -76,15 +77,17 @@ public:
     virtual ExecutionContext* executionContext() const override final;
 
 protected:
-    MIDIPort(MIDIAccess*, const String& id, const String& manufacturer, const String& name, TypeCode, const String& version, MIDIAccessor::MIDIPortState);
-
-private:
     enum ConnectionState {
         ConnectionStateOpen,
         ConnectionStateClosed,
         ConnectionStatePending
     };
 
+    MIDIPort(MIDIAccess*, const String& id, const String& manufacturer, const String& name, TypeCode, const String& version, MIDIAccessor::MIDIPortState);
+
+    void open();
+
+private:
     ScriptPromise accept(ScriptState*);
     ScriptPromise reject(ScriptState*, ExceptionCode, const String& message);