Fragment for measuring fps, heap size on Chrome

gistfile1.js

function() {
  var lastHeapSize = null;
  var lastFrameTime = null;

  var runGame = function() {
    requestAnimationFrame(runGame);

    var frameTime = window.performance.now();
    var heapSize = window.performance.memory.usedJSHeapSize;

    if (lastHeapSize == null) { lastHeapSize = heapSize; }
    if (lastFrameTime == null) { lastFrameTime = frameTime; }

    var dt = frameTime - lastFrameTime;
    var dh = heapSize - lastHeapSize

    frameDataList.push([dt, dh]);

    lastHeapSize = heapSize;
    lastFrameTime = frameTime;

    computeNextGameStateAndPaint();
  };
}();