Ask the animator if he wants frame updates for a given key path

CPViewAnimator.j

- (id)initWithTarget:(id)aTarget
{
    self = [super initWithTarget:aTarget];

    _wantsPeriodicFrameUpdates = NO;

    return self;
}

- (void)requestPeriodicFrameUpdates
{
    _wantsPeriodicFrameUpdates = YES;
}

- (void)_needsPeriodicFrameUpdatesForKeyPath:(CPString)aKeyPath
{
    return ((aKeyPath == @"frame" || aKeyPath == @"frameSize") && ([_target hasCustomLayoutSubviews] || [_target hasCustomDrawRect])) || _wantsPeriodicFrameUpdates;
}