Memory Leak with Phonegap Cordova Web Audio - ios

Question

I've seen this question asked here already : Web Audio API Memory Leaks on Mobile Platforms but there doesn't seem to be any response to it. I've tried lots of different variations - setting variables to null once I'm finished with them, or declaring the variables within scope, but it appears that the AudioContext (or OfflineAudioContext ) is not being Garbage collected after each operation. I'm using this with Phonegap, on an IOS, so the browser is safari. Any ideas how to solve this memory leak?
Here is my code:
function readVocalsToBuffer(file){
console.log('readVocalsToBuffer');
var reader = new FileReader();
reader.onloadend = function(evt){
var x = audioContext.decodeAudioData(evt.target._result, function(buffer){
if(!buffer){
console.log('error decoding file to Audio Buffer');
return;
}
window.voiceBuffer = buffer;
loadBuffers();
});
}
reader.readAsArrayBuffer(file);
}
function loadBuffers(){
console.log('loadBuffers');
try{
var bufferLoader = new BufferLoader(
audioContext,
[
"."+window.srcSong
],
createOffLineContext
);
bufferLoader.load()
}
catch(e){
console.log(e.message);
}
}
function createOffLineContext(bufferList){
console.log('createOfflineContext');
offline = new webkitOfflineAudioContext(2, window.voiceBuffer.length, 44100);
var vocalSource = offline.createBufferSource();
vocalSource.buffer = window.voiceBuffer;
vocalSource.connect(offline.destination);
var backing = offline.createBufferSource();
backing.buffer = bufferList[0];
backing.connect(offline.destination);
vocalSource.start(0);
backing.start(0);
offline.oncomplete = function(ev){
vocalSource.stop(0);
backing.stop(0);
vocalSource.disconnect(0);
backing.disconnect(0);
delete vocalSource;
delete backing;
delete window.voiceBuffer;
window.renderedFile = ev.renderedBuffer;
var bufferR = ev.renderedBuffer.getChannelData(0);
var bufferL = ev.renderedBuffer.getChannelData(1);
var interleaved = interleave(bufferL, bufferR);
var dataview = encodeWAV(interleaved);
window.audioBlob = new Blob([dataview], {type: 'Wav'});
saveFile();
}
offline.startRendering();
}
function interleave(inputL, inputR){
console.log('interleave');
var length = inputL.length + inputR.length;
var result = new Float32Array(length);
var index = 0,
inputIndex = 0;
while (index < length){
result[index++] = inputL[inputIndex];
result[index++] = inputR[inputIndex];
inputIndex++;
}
return result;
}
function saveFile(){
offline = null;
console.log('saveFile');
delete window.renderedFile;
window.requestFileSystem(LocalFileSystem.PERSISTENT, 0, onFSSuccess, fail);
}