getUserMedia API mock for audio

getUserMediaAudioMock.js

// This program is licensed under the MIT License.
navigator.webkitGetUserMedia = function(opt, ok, ng) {
  ok(null);
};
AudioContext.prototype.createMediaStreamSource = function() {
    var osc = this.createOscillator();
    osc.type = 'sine';
    var gain = this.createGain();
    gain.gain.value = 0.0;
    osc.connect(gain);
    osc.start(0);
    setInterval(function() {
        gain.gain.value = 0.5;
        setTimeout(function() { gain.gain.value = 0.0; }, 800);
    }, 1000);
    return gain;
};