Web MIDI: Add MIDIPortState state attribute to MIDIPort

Source/modules/webmidi/MIDIPort.idl

 /*
  * 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 10 matching lines @@
  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
+enum MIDIPortState {
+    "disconnected",
+    "connected",
+    "opened"
+};
+
 enum MIDIPortType {
     "input",
     "output"
 };
 
 [
     NoInterfaceObject,
     GarbageCollected
 ] interface MIDIPort : EventTarget {
     readonly attribute DOMString id;
     readonly attribute DOMString manufacturer;
     readonly attribute DOMString name;
+    readonly attribute MIDIPortState state;
     readonly attribute MIDIPortType type;
     readonly attribute DOMString version;
 
     attribute EventHandler ondisconnect;
 };