Bug 1066885 - [Camera] Record button flashes blue initially; video does ...

...not record, produces error message
Wouldn't if be more transparent to just have simple checks inside the functions that shouldn't be run when the camera is busy?

```js
Camera.prototype.takePicture = function() {
  if (this.isBusy) { return; }
  this.busy('takingPicture');

  // ... taking picture logic
};
```

This abstraction only seems to add unnecessary confusion IMO.