text: 
  // Refer: http://qiita.com/shinido/items/a80e5706f466b81646e2
  
  navigator.getUserMedia = navigator.getUserMedia || navigator.webkitGetUserMedia || navigator.mozGetUserMedia;
  var URL = window.URL || window.webkitURL;
  var RTCPeerConnection = window.RTCPeerConnection || window.webkitRTCPeerConnection || window.mozRTCPeerConnection;
  var RTCSessionDescription = window.RTCSessionDescription || window.webkitRTCSessionDescription || window.mozRTCSessionDescription;
  var RTCIceCandidate = window.RTCIceCandidate || window.webkitRTCIceCandidate || window.mozRTCIceCandidate;
  
  var mediaC = {
    'mandatory': {
      'OfferToReceiveAudio': true,
      'OfferToReceiveVideo': true
    }
  };
  var ice_config = {
    "iceServers": []
  };
  
  function getVideoSources(callback) {
    if (!navigator.mediaDevices) {
      console.log("MediaStreamTrack");
      MediaStreamTrack.getSources(function(cams) {
        cams.forEach(function(c, i, a) {
          if (c.kind != 'video') return;
          callback({
            name: c.facing,
            id: c.id
          });
        });
      });
    } else {
      navigator.mediaDevices.enumerateDevices().then(function(cams) {
        cams.forEach(function(c, i, a) {
          console.log("mediaDevices", c);
          if (c.kind != 'videoinput') return;
          callback({
            name: c.label,
            id: c.deviceId
          });
        });
      });
    }
  }
  
  