AnimationPlayer* play(Animation* animation, double startTime)
 {
     AnimationPlayer* player = timeline->play(animation);
     player->setStartTime(startTime * 1000);
     player->update(TimingUpdateOnDemand);
     return player;
 }
void CompositorPendingAnimations::notifyCompositorAnimationStarted(double monotonicAnimationStartTime)
{
    for (size_t i = 0; i < m_waitingForCompositorAnimationStart.size(); ++i) {
        AnimationPlayer* player = m_waitingForCompositorAnimationStart[i].get();
        player->setStartTime(monotonicAnimationStartTime - player->timeline()->zeroTime(), true);
        player->update(AnimationPlayer::UpdateOnDemand);
    }

    m_waitingForCompositorAnimationStart.clear();
}