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

Source/modules/webmidi/MIDIOutput.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 179 matching lines @@
 
 MIDIOutput::~MIDIOutput()
 {
 }
 
 void MIDIOutput::send(DOMUint8Array* array, double timestamp, ExceptionState& exceptionState)
 {
     if (timestamp == 0.0)
         timestamp = now(executionContext());
 
+    // Implicit open. It does nothing if the port is already opened.
+    // This should be performed even if |array| is invalid.
+    open();
+
     if (!array)
         return;
 
     if (MessageValidator::validate(array, exceptionState, midiAccess()->sysexEnabled()))
         midiAccess()->sendMIDIData(m_portIndex, array->data(), array->length(), timestamp);
 }
 
 void MIDIOutput::send(Vector<unsigned> unsignedData, double timestamp, ExceptionState& exceptionState)
 {
     if (timestamp == 0.0)
@@ skipping 24 matching lines @@
 {
     send(unsignedData, 0.0, exceptionState);
 }
 
 DEFINE_TRACE(MIDIOutput)
 {
     MIDIPort::trace(visitor);
 }
 
 } // namespace blink