Web MIDI: dispatch MIDIConnectionEvent

Source/modules/webmidi/MIDIMessageEvent.cpp

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "config.h"
 #include "modules/webmidi/MIDIMessageEvent.h"
+#include "modules/webmidi/MIDIMessageEventInit.h"
 
 namespace blink {
 
 MIDIMessageEvent::MIDIMessageEvent(const AtomicString& type, const MIDIMessageEventInit& initializer)
     : Event(type, initializer)
     , m_receivedTime(0.0)
 {
     if (initializer.hasReceivedTime())
         m_receivedTime = initializer.receivedTime();
     if (initializer.hasData())
         m_data = initializer.data();
 }
 
 } // namespace blink