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

Source/modules/webmidi/MIDIInput.cpp

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 32 matching lines @@
 {
     ASSERT(access);
     return new MIDIInput(access, id, manufacturer, name, version, state);
 }
 
 MIDIInput::MIDIInput(MIDIAccess* access, const String& id, const String& manufacturer, const String& name, const String& version, PortState state)
     : MIDIPort(access, id, manufacturer, name, TypeInput, version, state)
 {
 }
 
+EventListener* MIDIInput::onmidimessage()
+{
+    return getAttributeEventListener(EventTypeNames::midimessage);
+}
+
+void MIDIInput::setOnmidimessage(PassRefPtr<EventListener> listener)
+{
+    // Implicit open. It does nothing if the port is already opened.
+    // See http://www.w3.org/TR/webmidi/#widl-MIDIPort-open-Promise-MIDIPort
+    open();
+
+    setAttributeEventListener(EventTypeNames::midimessage, listener);
+}
+
 void MIDIInput::didReceiveMIDIData(unsigned portIndex, const unsigned char* data, size_t length, double timeStamp)
 {
     ASSERT(isMainThread());
 
     if (!length)
         return;
 
+    if (getConnection() != ConnectionStateOpen)
+        return;
+
     // Drop sysex message here when the client does not request it. Note that this is not a security check but an
     // automatic filtering for clients that do not want sysex message. Also note that sysex message will never be sent
     // unless the current process has an explicit permission to handle sysex message.
     if (data[0] == 0xf0 && !midiAccess()->sysexEnabled())
         return;
     RefPtr<DOMUint8Array> array = DOMUint8Array::create(data, length);
     dispatchEvent(MIDIMessageEvent::create(timeStamp, array));
 }
 
 DEFINE_TRACE(MIDIInput)
 {
     MIDIPort::trace(visitor);
 }
 
 } // namespace blink