function RotateInstructions() {
  this.loadIcon_();

  var overlay = document.createElement('div');
  var s = overlay.style;
  s.position = 'fixed';
  s.top = 0;
  s.right = 0;
  s.bottom = 0;
  s.left = 0;
  s.backgroundColor = 'gray';
  s.fontFamily = 'sans-serif';
  // Force this to be above the fullscreen canvas, which is at zIndex: 999999.
  s.zIndex = 1000000;

  var img = document.createElement('img');
  img.src = this.icon;
  var s = img.style;
  s.marginLeft = '25%';
  s.marginTop = '25%';
  s.width = '50%';
  overlay.appendChild(img);

  var text = document.createElement('div');
  var s = text.style;
  s.textAlign = 'center';
  s.fontSize = '16px';
  s.lineHeight = '24px';
  s.margin = '24px 25%';
  s.width = '50%';
  text.innerHTML = 'Place your phone into your Cardboard viewer.';
  overlay.appendChild(text);

  var snackbar = document.createElement('div');
  var s = snackbar.style;
  s.backgroundColor = '#CFD8DC';
  s.position = 'fixed';
  s.bottom = 0;
  s.width = '100%';
  s.height = '48px';
  s.padding = '14px 24px';
  s.boxSizing = 'border-box';
  s.color = '#656A6B';
  overlay.appendChild(snackbar);

  var snackbarText = document.createElement('div');
  snackbarText.style.float = 'left';
  snackbarText.innerHTML = 'No Cardboard viewer?';

  var snackbarButton = document.createElement('a');
  snackbarButton.href = 'https://www.google.com/get/cardboard/get-cardboard/';
  snackbarButton.innerHTML = 'get one';
  snackbarButton.target = '_blank';
  var s = snackbarButton.style;
  s.float = 'right';
  s.fontWeight = 600;
  s.textTransform = 'uppercase';
  s.borderLeft = '1px solid gray';
  s.paddingLeft = '24px';
  s.textDecoration = 'none';
  s.color = '#656A6B';

  snackbar.appendChild(snackbarText);
  snackbar.appendChild(snackbarButton);

  this.overlay = overlay;
  this.text = text;

  this.hide();
}
Start an animation to transition an angle from one value to another.