AnimationPlayerCollection*
CommonAnimationManager::GetAnimationsForCompositor(nsIContent* aContent,
                                                   nsIAtom* aElementProperty,
                                                   nsCSSProperty aProperty)
{
  if (!aContent->MayHaveAnimations())
    return nullptr;

  AnimationPlayerCollection* collection =
    static_cast<AnimationPlayerCollection*>(
      aContent->GetProperty(aElementProperty));
  if (!collection ||
      !collection->HasAnimationOfProperty(aProperty) ||
      !collection->CanPerformOnCompositorThread(
        AnimationPlayerCollection::CanAnimate_AllowPartial)) {
    return nullptr;
  }

  // This animation can be done on the compositor.
  return collection;
}
void
nsAnimationManager::FlushAnimations(FlushFlags aFlags)
{
  // FIXME: check that there's at least one style rule that's not
  // in its "done" state, and if there isn't, remove ourselves from
  // the refresh driver (but leave the animations!).
  TimeStamp now = mPresContext->RefreshDriver()->MostRecentRefresh();
  bool didThrottle = false;
  for (PRCList *l = PR_LIST_HEAD(&mElementCollections);
       l != &mElementCollections;
       l = PR_NEXT_LINK(l)) {
    AnimationPlayerCollection* collection =
      static_cast<AnimationPlayerCollection*>(l);

    nsAutoAnimationMutationBatch mb(collection->mElement);

    collection->Tick();
    bool canThrottleTick = aFlags == Can_Throttle &&
      collection->CanPerformOnCompositorThread(
        AnimationPlayerCollection::CanAnimateFlags(0)) &&
      collection->CanThrottleAnimation(now);

    nsRefPtr<css::AnimValuesStyleRule> oldStyleRule = collection->mStyleRule;
    UpdateStyleAndEvents(collection, now, canThrottleTick
                                          ? EnsureStyleRule_IsThrottled
                                          : EnsureStyleRule_IsNotThrottled);
    if (oldStyleRule != collection->mStyleRule) {
      collection->PostRestyleForAnimation(mPresContext);
    } else {
      didThrottle = true;
    }
  }

  if (didThrottle) {
    mPresContext->Document()->SetNeedStyleFlush();
  }

  DispatchEvents(); // may destroy us
}