Prevent OSX Safari to display distorted map

This PR fixes #1698.

Safari isn’t really fullscreen when the `resize` event is triggered ; the following code:

```javascript
var resize = function() {
  console.log(document.webkitIsFullScreen);
  console.log(document.mozFullScreen);
  setTimeout(function() {
    console.log(document.webkitIsFullScreen);
    console.log(document.mozFullScreen);
  }, 0);
};
window.addEventListener('resize', resize, false);
 ```

returns `true,true` on Firefox and `false,true` on safari when going fullscreen.

A call to `updateSize` in the `handleFullScreenChange_`, triggered when the page really have its new dimension, fixes Safari’s bad behavior.