CC Animation: Merge LayerAnimationController into ElementAnimations.

cc/animation/element_animations.cc

Index: cc/animation/element_animations.cc
diff --git a/cc/animation/element_animations.cc b/cc/animation/element_animations.cc
index 6cf9ea35ce2a6313a49c3ae3f9ec2dfd64af331d..308fa1fcd77eb8ecfb28d98510f4fa19a9bb1c90 100644
--- a/cc/animation/element_animations.cc
+++ b/cc/animation/element_animations.cc
@@ -4,84 +4,97 @@
 
 #include "cc/animation/element_animations.h"
 
+#include <stddef.h>
+
+#include <algorithm>
+
 #include "base/macros.h"
 #include "base/memory/ptr_util.h"
+#include "cc/animation/animation_delegate.h"
 #include "cc/animation/animation_host.h"
 #include "cc/animation/animation_player.h"
+#include "cc/animation/keyframed_animation_curve.h"
+#include "cc/animation/scroll_offset_animation_curve.h"
+#include "cc/output/filter_operations.h"
 #include "cc/trees/mutator_host_client.h"
+#include "ui/gfx/geometry/box_f.h"
 
 namespace cc {
 
-scoped_refptr<ElementAnimations> ElementAnimations::Create(
-    AnimationHost* host) {
-  return make_scoped_refptr(new ElementAnimations(host));
+scoped_refptr<ElementAnimations> ElementAnimations::Create() {
+  return make_scoped_refptr(new ElementAnimations());
 }
 
-ElementAnimations::ElementAnimations(AnimationHost* host)
-    : players_list_(new PlayersList()), animation_host_(host) {
-  DCHECK(animation_host_);
+ElementAnimations::ElementAnimations()
+    : players_list_(new PlayersList()),
+      animation_host_(),
+      layer_id_(),
+      is_active_(false),
+      needs_active_value_observations_(false),
+      needs_pending_value_observations_(false),
+      needs_to_start_animations_(false),
+      scroll_offset_animation_was_interrupted_(false),
+      potentially_animating_transform_for_active_observers_(false),
+      potentially_animating_transform_for_pending_observers_(false) {}
+
+ElementAnimations::~ElementAnimations() {}
+
+void ElementAnimations::SetAnimationHost(AnimationHost* host) {
+  animation_host_ = host;
 }
 
-ElementAnimations::~ElementAnimations() {
-  DCHECK(!layer_animation_controller_);
+void ElementAnimations::SetLayerId(int layer_id) {
+  layer_id_ = layer_id;
 }
 
-void ElementAnimations::CreateLayerAnimationController(int layer_id) {
-  DCHECK(layer_id);
-  DCHECK(!layer_animation_controller_);
+void ElementAnimations::InitValueObservations() {
+  DCHECK(layer_id_);
   DCHECK(animation_host_);
 
-  layer_animation_controller_ =
-      animation_host_->GetAnimationControllerForId(layer_id);
-  layer_animation_controller_->SetAnimationHost(animation_host_);
-  layer_animation_controller_->set_layer_animation_delegate(this);
-  layer_animation_controller_->set_value_observer(this);
-  layer_animation_controller_->set_value_provider(this);
+  UpdateActivation(FORCE_ACTIVATION);
 
   DCHECK(animation_host_->mutator_host_client());
   if (animation_host_->mutator_host_client()->IsLayerInTree(
-          layer_id, LayerTreeType::ACTIVE))
-    CreateActiveValueObserver();
+          layer_id_, LayerTreeType::ACTIVE)) {
+    set_needs_active_value_observations(true);
+  }
   if (animation_host_->mutator_host_client()->IsLayerInTree(
-          layer_id, LayerTreeType::PENDING))
-    CreatePendingValueObserver();
+          layer_id_, LayerTreeType::PENDING)) {
+    set_needs_pending_value_observations(true);
+  }
 }
 
-void ElementAnimations::DestroyLayerAnimationController() {
+void ElementAnimations::ClearValueObservations() {
   DCHECK(animation_host_);
 
   if (needs_active_value_observations())
     OnTransformIsPotentiallyAnimatingChanged(LayerTreeType::ACTIVE, false);
+  set_needs_active_value_observations(false);
+
   if (needs_pending_value_observations())
     OnTransformIsPotentiallyAnimatingChanged(LayerTreeType::PENDING, false);
+  set_needs_pending_value_observations(false);
 
-  DestroyPendingValueObserver();
-  DestroyActiveValueObserver();
-
-  if (layer_animation_controller_) {
-    layer_animation_controller_->remove_value_provider(this);
-    layer_animation_controller_->set_value_observer(nullptr);
-    layer_animation_controller_->remove_layer_animation_delegate(this);
-    layer_animation_controller_->SetAnimationHost(nullptr);
-    layer_animation_controller_ = nullptr;
-  }
+  animation_host_->DidDeactivateElementAnimations(this);
+  UpdateActivation(FORCE_ACTIVATION);
 }
 
 void ElementAnimations::LayerRegistered(int layer_id, LayerTreeType tree_type) {
-  DCHECK(layer_animation_controller_);
-  DCHECK_EQ(layer_animation_controller_->id(), layer_id);
+  DCHECK_EQ(layer_id_, layer_id);
 
   if (tree_type == LayerTreeType::ACTIVE)
-    layer_animation_controller_->set_needs_active_value_observations(true);
+    set_needs_active_value_observations(true);
   else
-    layer_animation_controller_->set_needs_pending_value_observations(true);
+    set_needs_pending_value_observations(true);
 }
 
 void ElementAnimations::LayerUnregistered(int layer_id,
                                           LayerTreeType tree_type) {
   DCHECK_EQ(this->layer_id(), layer_id);
-  tree_type == LayerTreeType::ACTIVE ? DestroyActiveValueObserver()
-                                     : DestroyPendingValueObserver();
+  if (tree_type == LayerTreeType::ACTIVE)
+    set_needs_active_value_observations(false);
+  else
+    set_needs_pending_value_observations(false);
 }
 
 void ElementAnimations::AddPlayer(AnimationPlayer* player) {
@@ -104,43 +117,1130 @@ bool ElementAnimations::IsEmpty() const {
 
 void ElementAnimations::PushPropertiesTo(
     scoped_refptr<ElementAnimations> element_animations_impl) {
-  DCHECK(layer_animation_controller_);
-  DCHECK(element_animations_impl->layer_animation_controller_);
+  DCHECK_NE(this, element_animations_impl);
+  if (!has_any_animation() && !element_animations_impl->has_any_animation())
+    return;
+  MarkAbortedAnimationsForDeletion(element_animations_impl.get());
+  PurgeAnimationsMarkedForDeletion();
+  PushNewAnimationsToImplThread(element_animations_impl.get());
 
-  layer_animation_controller_->PushAnimationUpdatesTo(
-      element_animations_impl->layer_animation_controller_.get());
+  // Remove finished impl side animations only after pushing,
+  // and only after the animations are deleted on the main thread
+  // this insures we will never push an animation twice.
+  RemoveAnimationsCompletedOnMainThread(element_animations_impl.get());
+
+  PushPropertiesToImplThread(element_animations_impl.get());
+  element_animations_impl->UpdateActivation(NORMAL_ACTIVATION);
+  UpdateActivation(NORMAL_ACTIVATION);
 }
 
 void ElementAnimations::AddAnimation(std::unique_ptr<Animation> animation) {
-  layer_animation_controller_->AddAnimation(std::move(animation));
+  bool added_transform_animation =
+      animation->target_property() == TargetProperty::TRANSFORM;
+  animations_.push_back(std::move(animation));
+  needs_to_start_animations_ = true;
+  UpdateActivation(NORMAL_ACTIVATION);
+  if (added_transform_animation)
+    UpdatePotentiallyAnimatingTransform();
+}
+
+void ElementAnimations::Animate(base::TimeTicks monotonic_time) {
+  DCHECK(!monotonic_time.is_null());
+  if (!needs_active_value_observations() && !needs_pending_value_observations())
+    return;
+
+  if (needs_to_start_animations_)
+    StartAnimations(monotonic_time);
+  TickAnimations(monotonic_time);
+  last_tick_time_ = monotonic_time;
+}
+
+void ElementAnimations::AccumulatePropertyUpdates(
+    base::TimeTicks monotonic_time,
+    AnimationEvents* events) {
+  if (!events)
+    return;
+
+  for (size_t i = 0; i < animations_.size(); ++i) {
+    Animation* animation = animations_[i].get();
+    if (!animation->is_impl_only())
+      continue;
+
+    if (!animation->InEffect(monotonic_time))
+      continue;
+
+    base::TimeDelta trimmed =
+        animation->TrimTimeToCurrentIteration(monotonic_time);
+    switch (animation->target_property()) {
+      case TargetProperty::OPACITY: {
+        AnimationEvent event(AnimationEvent::PROPERTY_UPDATE, layer_id_,
+                             animation->group(), TargetProperty::OPACITY,
+                             monotonic_time);
+        const FloatAnimationCurve* float_animation_curve =
+            animation->curve()->ToFloatAnimationCurve();
+        event.opacity = float_animation_curve->GetValue(trimmed);
+        event.is_impl_only = true;
+        events->events_.push_back(event);
+        break;
+      }
+
+      case TargetProperty::TRANSFORM: {
+        AnimationEvent event(AnimationEvent::PROPERTY_UPDATE, layer_id_,
+                             animation->group(), TargetProperty::TRANSFORM,
+                             monotonic_time);
+        const TransformAnimationCurve* transform_animation_curve =
+            animation->curve()->ToTransformAnimationCurve();
+        event.transform = transform_animation_curve->GetValue(trimmed);
+        event.is_impl_only = true;
+        events->events_.push_back(event);
+        break;
+      }
+
+      case TargetProperty::FILTER: {
+        AnimationEvent event(AnimationEvent::PROPERTY_UPDATE, layer_id_,
+                             animation->group(), TargetProperty::FILTER,
+                             monotonic_time);
+        const FilterAnimationCurve* filter_animation_curve =
+            animation->curve()->ToFilterAnimationCurve();
+        event.filters = filter_animation_curve->GetValue(trimmed);
+        event.is_impl_only = true;
+        events->events_.push_back(event);
+        break;
+      }
+
+      case TargetProperty::BACKGROUND_COLOR: {
+        break;
+      }
+
+      case TargetProperty::SCROLL_OFFSET: {
+        // Impl-side changes to scroll offset are already sent back to the
+        // main thread (e.g. for user-driven scrolling), so a PROPERTY_UPDATE
+        // isn't needed.
+        break;
+      }
+    }
+  }
+}
+
+void ElementAnimations::UpdateState(bool start_ready_animations,
+                                    AnimationEvents* events) {
+  if (!needs_active_value_observations())
+    return;
+
+  // Animate hasn't been called, this happens if an observer has been added
+  // between the Commit and Draw phases.
+  if (last_tick_time_ == base::TimeTicks())
+    return;
+
+  if (start_ready_animations)
+    PromoteStartedAnimations(last_tick_time_, events);
+
+  MarkFinishedAnimations(last_tick_time_);
+  MarkAnimationsForDeletion(last_tick_time_, events);
+
+  if (needs_to_start_animations_ && start_ready_animations) {
+    StartAnimations(last_tick_time_);
+    PromoteStartedAnimations(last_tick_time_, events);
+  }
+
+  AccumulatePropertyUpdates(last_tick_time_, events);
+
+  UpdateActivation(NORMAL_ACTIVATION);
+}
+
+void ElementAnimations::ActivateAnimations() {
+  bool changed_transform_animation = false;
+  for (size_t i = 0; i < animations_.size(); ++i) {
+    if (animations_[i]->affects_active_observers() !=
+            animations_[i]->affects_pending_observers() &&
+        animations_[i]->target_property() == TargetProperty::TRANSFORM)
+      changed_transform_animation = true;
+    animations_[i]->set_affects_active_observers(
+        animations_[i]->affects_pending_observers());
+  }
+  auto affects_no_observers = [](const std::unique_ptr<Animation>& animation) {
+    return !animation->affects_active_observers() &&
+           !animation->affects_pending_observers();
+  };
+  animations_.erase(std::remove_if(animations_.begin(), animations_.end(),
+                                   affects_no_observers),
+                    animations_.end());
+  scroll_offset_animation_was_interrupted_ = false;
+  UpdateActivation(NORMAL_ACTIVATION);
+  if (changed_transform_animation)
+    UpdatePotentiallyAnimatingTransform();
+}
+
+void ElementAnimations::NotifyAnimationStarted(const AnimationEvent& event) {
+  if (event.is_impl_only) {
+    NotifyPlayersAnimationStarted(event.monotonic_time, event.target_property,
+                                  event.group_id);
+    return;
+  }
+
+  for (size_t i = 0; i < animations_.size(); ++i) {
+    if (animations_[i]->group() == event.group_id &&
+        animations_[i]->target_property() == event.target_property &&
+        animations_[i]->needs_synchronized_start_time()) {
+      animations_[i]->set_needs_synchronized_start_time(false);
+      if (!animations_[i]->has_set_start_time())
+        animations_[i]->set_start_time(event.monotonic_time);
+
+      NotifyPlayersAnimationStarted(event.monotonic_time, event.target_property,
+                                    event.group_id);
+
+      return;
+    }
+  }
+}
+
+void ElementAnimations::NotifyAnimationFinished(const AnimationEvent& event) {
+  if (event.is_impl_only) {
+    NotifyPlayersAnimationFinished(event.monotonic_time, event.target_property,
+                                   event.group_id);
+    return;
+  }
+
+  for (size_t i = 0; i < animations_.size(); ++i) {
+    if (animations_[i]->group() == event.group_id &&
+        animations_[i]->target_property() == event.target_property) {
+      animations_[i]->set_received_finished_event(true);
+      NotifyPlayersAnimationFinished(event.monotonic_time,
+                                     event.target_property, event.group_id);
+
+      return;
+    }
+  }
+}
+
+void ElementAnimations::NotifyAnimationTakeover(const AnimationEvent& event) {
+  DCHECK(event.target_property == TargetProperty::SCROLL_OFFSET);
+  if (!players_list_->empty()) {
+    std::unique_ptr<AnimationCurve> animation_curve = event.curve->Clone();
+    NotifyPlayersAnimationTakeover(event.monotonic_time, event.target_property,
+                                   event.animation_start_time,
+                                   std::move(animation_curve));
+  }
+}
+
+void ElementAnimations::NotifyAnimationAborted(const AnimationEvent& event) {
+  bool aborted_transform_animation = false;
+  for (size_t i = 0; i < animations_.size(); ++i) {
+    if (animations_[i]->group() == event.group_id &&
+        animations_[i]->target_property() == event.target_property) {
+      animations_[i]->SetRunState(Animation::ABORTED, event.monotonic_time);
+      animations_[i]->set_received_finished_event(true);
+      NotifyPlayersAnimationAborted(event.monotonic_time, event.target_property,
+                                    event.group_id);
+      if (event.target_property == TargetProperty::TRANSFORM)
+        aborted_transform_animation = true;
+      break;
+    }
+  }
+  if (aborted_transform_animation)
+    UpdatePotentiallyAnimatingTransform();
+}
+
+void ElementAnimations::NotifyAnimationPropertyUpdate(
+    const AnimationEvent& event) {
+  bool notify_active_observers = true;
+  bool notify_pending_observers = true;
+  switch (event.target_property) {
+    case TargetProperty::OPACITY:
+      NotifyObserversOpacityAnimated(event.opacity, notify_active_observers,
+                                     notify_pending_observers);
+      break;
+    case TargetProperty::TRANSFORM:
+      NotifyObserversTransformAnimated(event.transform, notify_active_observers,
+                                       notify_pending_observers);
+      break;
+    default:
+      NOTREACHED();
+  }
+}
+
+bool ElementAnimations::HasFilterAnimationThatInflatesBounds() const {
+  for (size_t i = 0; i < animations_.size(); ++i) {
+    if (!animations_[i]->is_finished() &&
+        animations_[i]->target_property() == TargetProperty::FILTER &&
+        animations_[i]
+            ->curve()
+            ->ToFilterAnimationCurve()
+            ->HasFilterThatMovesPixels())
+      return true;
+  }
+
+  return false;
+}
+
+bool ElementAnimations::HasTransformAnimationThatInflatesBounds() const {
+  return IsCurrentlyAnimatingProperty(TargetProperty::TRANSFORM,
+                                      ObserverType::ACTIVE) ||
+         IsCurrentlyAnimatingProperty(TargetProperty::TRANSFORM,
+                                      ObserverType::PENDING);
+}
+
+bool ElementAnimations::FilterAnimationBoundsForBox(const gfx::BoxF& box,
+                                                    gfx::BoxF* bounds) const {
+  // TODO(avallee): Implement.
+  return false;
+}
+
+bool ElementAnimations::TransformAnimationBoundsForBox(
+    const gfx::BoxF& box,
+    gfx::BoxF* bounds) const {
+  DCHECK(HasTransformAnimationThatInflatesBounds())
+      << "TransformAnimationBoundsForBox will give incorrect results if there "
+      << "are no transform animations affecting bounds, non-animated transform "
+      << "is not known";
+
+  // Compute bounds based on animations for which is_finished() is false.
+  // Do nothing if there are no such animations; in this case, it is assumed
+  // that callers will take care of computing bounds based on the owning layer's
+  // actual transform.
+  *bounds = gfx::BoxF();
+  for (size_t i = 0; i < animations_.size(); ++i) {
+    if (animations_[i]->is_finished() ||
+        animations_[i]->target_property() != TargetProperty::TRANSFORM)
+      continue;
+
+    const TransformAnimationCurve* transform_animation_curve =
+        animations_[i]->curve()->ToTransformAnimationCurve();
+    gfx::BoxF animation_bounds;
+    bool success =
+        transform_animation_curve->AnimatedBoundsForBox(box, &animation_bounds);
+    if (!success)
+      return false;
+    bounds->Union(animation_bounds);
+  }
+
+  return true;
+}
+
+bool ElementAnimations::HasAnimationThatAffectsScale() const {
+  for (size_t i = 0; i < animations_.size(); ++i) {
+    if (animations_[i]->is_finished() ||
+        animations_[i]->target_property() != TargetProperty::TRANSFORM)
+      continue;
+
+    const TransformAnimationCurve* transform_animation_curve =
+        animations_[i]->curve()->ToTransformAnimationCurve();
+    if (transform_animation_curve->AffectsScale())
+      return true;
+  }
+
+  return false;
+}
+
+bool ElementAnimations::HasOnlyTranslationTransforms(
+    ObserverType observer_type) const {
+  for (size_t i = 0; i < animations_.size(); ++i) {
+    if (animations_[i]->is_finished() ||
+        animations_[i]->target_property() != TargetProperty::TRANSFORM)
+      continue;
+
+    if ((observer_type == ObserverType::ACTIVE &&
+         !animations_[i]->affects_active_observers()) ||
+        (observer_type == ObserverType::PENDING &&
+         !animations_[i]->affects_pending_observers()))
+      continue;
+
+    const TransformAnimationCurve* transform_animation_curve =
+        animations_[i]->curve()->ToTransformAnimationCurve();
+    if (!transform_animation_curve->IsTranslation())
+      return false;
+  }
+
+  return true;
+}
+
+bool ElementAnimations::AnimationsPreserveAxisAlignment() const {
+  for (size_t i = 0; i < animations_.size(); ++i) {
+    if (animations_[i]->is_finished() ||
+        animations_[i]->target_property() != TargetProperty::TRANSFORM)
+      continue;
+
+    const TransformAnimationCurve* transform_animation_curve =
+        animations_[i]->curve()->ToTransformAnimationCurve();
+    if (!transform_animation_curve->PreservesAxisAlignment())
+      return false;
+  }
+
+  return true;
+}
+
+bool ElementAnimations::AnimationStartScale(ObserverType observer_type,
+                                            float* start_scale) const {
+  *start_scale = 0.f;
+  for (size_t i = 0; i < animations_.size(); ++i) {
+    if (animations_[i]->is_finished() ||
+        animations_[i]->target_property() != TargetProperty::TRANSFORM)
+      continue;
+
+    if ((observer_type == ObserverType::ACTIVE &&
+         !animations_[i]->affects_active_observers()) ||
+        (observer_type == ObserverType::PENDING &&
+         !animations_[i]->affects_pending_observers()))
+      continue;
+
+    bool forward_direction = true;
+    switch (animations_[i]->direction()) {
+      case Animation::DIRECTION_NORMAL:
+      case Animation::DIRECTION_ALTERNATE:
+        forward_direction = animations_[i]->playback_rate() >= 0.0;
+        break;
+      case Animation::DIRECTION_REVERSE:
+      case Animation::DIRECTION_ALTERNATE_REVERSE:
+        forward_direction = animations_[i]->playback_rate() < 0.0;
+        break;
+    }
+
+    const TransformAnimationCurve* transform_animation_curve =
+        animations_[i]->curve()->ToTransformAnimationCurve();
+    float animation_start_scale = 0.f;
+    if (!transform_animation_curve->AnimationStartScale(forward_direction,
+                                                        &animation_start_scale))
+      return false;
+    *start_scale = std::max(*start_scale, animation_start_scale);
+  }
+  return true;
+}
+
+bool ElementAnimations::MaximumTargetScale(ObserverType observer_type,
+                                           float* max_scale) const {
+  *max_scale = 0.f;
+  for (size_t i = 0; i < animations_.size(); ++i) {
+    if (animations_[i]->is_finished() ||
+        animations_[i]->target_property() != TargetProperty::TRANSFORM)
+      continue;
+
+    if ((observer_type == ObserverType::ACTIVE &&
+         !animations_[i]->affects_active_observers()) ||
+        (observer_type == ObserverType::PENDING &&
+         !animations_[i]->affects_pending_observers()))
+      continue;
+
+    bool forward_direction = true;
+    switch (animations_[i]->direction()) {
+      case Animation::DIRECTION_NORMAL:
+      case Animation::DIRECTION_ALTERNATE:
+        forward_direction = animations_[i]->playback_rate() >= 0.0;
+        break;
+      case Animation::DIRECTION_REVERSE:
+      case Animation::DIRECTION_ALTERNATE_REVERSE:
+        forward_direction = animations_[i]->playback_rate() < 0.0;
+        break;
+    }
+
+    const TransformAnimationCurve* transform_animation_curve =
+        animations_[i]->curve()->ToTransformAnimationCurve();
+    float animation_scale = 0.f;
+    if (!transform_animation_curve->MaximumTargetScale(forward_direction,
+                                                       &animation_scale))
+      return false;
+    *max_scale = std::max(*max_scale, animation_scale);
+  }
+
+  return true;
+}
+
+void ElementAnimations::PushNewAnimationsToImplThread(
+    ElementAnimations* element_animations_impl) const {
+  // Any new animations owned by the main thread's ElementAnimations are cloned
+  // and added to the impl thread's ElementAnimations.
+  for (size_t i = 0; i < animations_.size(); ++i) {
+    // If the animation is already running on the impl thread, there is no
+    // need to copy it over.
+    if (element_animations_impl->GetAnimationById(animations_[i]->id()))
+      continue;
+
+    if (animations_[i]->target_property() == TargetProperty::SCROLL_OFFSET &&
+        !animations_[i]
+             ->curve()
+             ->ToScrollOffsetAnimationCurve()
+             ->HasSetInitialValue()) {
+      gfx::ScrollOffset current_scroll_offset;
+      if (element_animations_impl->needs_active_value_observations()) {
+        current_scroll_offset =
+            element_animations_impl->ScrollOffsetForAnimation();
+      } else {
+        // The owning layer isn't yet in the active tree, so the main thread
+        // scroll offset will be up-to-date.
+        current_scroll_offset = ScrollOffsetForAnimation();
+      }
+      animations_[i]->curve()->ToScrollOffsetAnimationCurve()->SetInitialValue(
+          current_scroll_offset);
+    }
+
+    // The new animation should be set to run as soon as possible.
+    Animation::RunState initial_run_state =
+        Animation::WAITING_FOR_TARGET_AVAILABILITY;
+    std::unique_ptr<Animation> to_add(
+        animations_[i]->CloneAndInitialize(initial_run_state));
+    DCHECK(!to_add->needs_synchronized_start_time());
+    to_add->set_affects_active_observers(false);
+    element_animations_impl->AddAnimation(std::move(to_add));
+  }
+}
+
+static bool IsCompleted(
+    Animation* animation,
+    const ElementAnimations* main_thread_element_animations) {
+  if (animation->is_impl_only()) {
+    return (animation->run_state() == Animation::WAITING_FOR_DELETION);
+  } else {
+    return !main_thread_element_animations->GetAnimationById(animation->id());
+  }
+}
+
+void ElementAnimations::RemoveAnimationsCompletedOnMainThread(
+    ElementAnimations* element_animations_impl) const {
+  bool removed_transform_animation = false;
+  // Animations removed on the main thread should no longer affect pending
+  // observers, and should stop affecting active observers after the next call
+  // to ActivateAnimations. If already WAITING_FOR_DELETION, they can be removed
+  // immediately.
+  auto& animations = element_animations_impl->animations_;
+  for (const auto& animation : animations) {
+    if (IsCompleted(animation.get(), this)) {
+      animation->set_affects_pending_observers(false);
+      if (animation->target_property() == TargetProperty::TRANSFORM)
+        removed_transform_animation = true;
+    }
+  }
+  auto affects_active_only_and_is_waiting_for_deletion =
+      [](const std::unique_ptr<Animation>& animation) {
+        return animation->run_state() == Animation::WAITING_FOR_DELETION &&
+               !animation->affects_pending_observers();
+      };
+  animations.erase(
+      std::remove_if(animations.begin(), animations.end(),
+                     affects_active_only_and_is_waiting_for_deletion),
+      animations.end());
+
+  if (removed_transform_animation)
+    element_animations_impl->UpdatePotentiallyAnimatingTransform();
+}
+
+void ElementAnimations::PushPropertiesToImplThread(
+    ElementAnimations* element_animations_impl) {
+  for (size_t i = 0; i < animations_.size(); ++i) {
+    Animation* current_impl =
+        element_animations_impl->GetAnimationById(animations_[i]->id());
+    if (current_impl)
+      animations_[i]->PushPropertiesTo(current_impl);
+  }
+  element_animations_impl->scroll_offset_animation_was_interrupted_ =
+      scroll_offset_animation_was_interrupted_;
+  scroll_offset_animation_was_interrupted_ = false;
+}
+
+void ElementAnimations::StartAnimations(base::TimeTicks monotonic_time) {
+  DCHECK(needs_to_start_animations_);
+  needs_to_start_animations_ = false;
+  // First collect running properties affecting each type of observer.
+  TargetProperties blocked_properties_for_active_observers;
+  TargetProperties blocked_properties_for_pending_observers;
+  std::vector<size_t> animations_waiting_for_target;
+
+  animations_waiting_for_target.reserve(animations_.size());
+  for (size_t i = 0; i < animations_.size(); ++i) {
+    if (animations_[i]->run_state() == Animation::STARTING ||
+        animations_[i]->run_state() == Animation::RUNNING) {
+      if (animations_[i]->affects_active_observers()) {
+        blocked_properties_for_active_observers[animations_[i]
+                                                    ->target_property()] = true;
+      }
+      if (animations_[i]->affects_pending_observers()) {
+        blocked_properties_for_pending_observers[animations_[i]
+                                                     ->target_property()] =
+            true;
+      }
+    } else if (animations_[i]->run_state() ==
+               Animation::WAITING_FOR_TARGET_AVAILABILITY) {
+      animations_waiting_for_target.push_back(i);
+    }
+  }
+
+  for (size_t i = 0; i < animations_waiting_for_target.size(); ++i) {
+    // Collect all properties for animations with the same group id (they
+    // should all also be in the list of animations).
+    size_t animation_index = animations_waiting_for_target[i];
+    Animation* animation_waiting_for_target =
+        animations_[animation_index].get();
+    // Check for the run state again even though the animation was waiting
+    // for target because it might have changed the run state while handling
+    // previous animation in this loop (if they belong to same group).
+    if (animation_waiting_for_target->run_state() ==
+        Animation::WAITING_FOR_TARGET_AVAILABILITY) {
+      TargetProperties enqueued_properties;
+      bool affects_active_observers =
+          animation_waiting_for_target->affects_active_observers();
+      bool affects_pending_observers =
+          animation_waiting_for_target->affects_pending_observers();
+      enqueued_properties[animation_waiting_for_target->target_property()] =
+          true;
+      for (size_t j = animation_index + 1; j < animations_.size(); ++j) {
+        if (animation_waiting_for_target->group() == animations_[j]->group()) {
+          enqueued_properties[animations_[j]->target_property()] = true;
+          affects_active_observers |=
+              animations_[j]->affects_active_observers();
+          affects_pending_observers |=
+              animations_[j]->affects_pending_observers();
+        }
+      }
+
+      // Check to see if intersection of the list of properties affected by
+      // the group and the list of currently blocked properties is null, taking
+      // into account the type(s) of observers affected by the group. In any
+      // case, the group's target properties need to be added to the lists of
+      // blocked properties.
+      bool null_intersection = true;
+      static_assert(TargetProperty::FIRST_TARGET_PROPERTY == 0,
+                    "TargetProperty must be 0-based enum");
+      for (int property = TargetProperty::FIRST_TARGET_PROPERTY;
+           property <= TargetProperty::LAST_TARGET_PROPERTY; ++property) {
+        if (enqueued_properties[property]) {
+          if (affects_active_observers) {
+            if (blocked_properties_for_active_observers[property])
+              null_intersection = false;
+            else
+              blocked_properties_for_active_observers[property] = true;
+          }
+          if (affects_pending_observers) {
+            if (blocked_properties_for_pending_observers[property])
+              null_intersection = false;
+            else
+              blocked_properties_for_pending_observers[property] = true;
+          }
+        }
+      }
+
+      // If the intersection is null, then we are free to start the animations
+      // in the group.
+      if (null_intersection) {
+        animation_waiting_for_target->SetRunState(Animation::STARTING,
+                                                  monotonic_time);
+        for (size_t j = animation_index + 1; j < animations_.size(); ++j) {
+          if (animation_waiting_for_target->group() ==
+              animations_[j]->group()) {
+            animations_[j]->SetRunState(Animation::STARTING, monotonic_time);
+          }
+        }
+      } else {
+        needs_to_start_animations_ = true;
+      }
+    }
+  }
+}
+
+void ElementAnimations::PromoteStartedAnimations(base::TimeTicks monotonic_time,
+                                                 AnimationEvents* events) {
+  for (size_t i = 0; i < animations_.size(); ++i) {
+    if (animations_[i]->run_state() == Animation::STARTING &&
+        animations_[i]->affects_active_observers()) {
+      animations_[i]->SetRunState(Animation::RUNNING, monotonic_time);
+      if (!animations_[i]->has_set_start_time() &&
+          !animations_[i]->needs_synchronized_start_time())
+        animations_[i]->set_start_time(monotonic_time);
+      if (events) {
+        base::TimeTicks start_time;
+        if (animations_[i]->has_set_start_time())
+          start_time = animations_[i]->start_time();
+        else
+          start_time = monotonic_time;
+        AnimationEvent started_event(
+            AnimationEvent::STARTED, layer_id_, animations_[i]->group(),
+            animations_[i]->target_property(), start_time);
+        started_event.is_impl_only = animations_[i]->is_impl_only();
+        if (started_event.is_impl_only)
+          NotifyAnimationStarted(started_event);
+        else
+          events->events_.push_back(started_event);
+      }
+    }
+  }
+}
+
+void ElementAnimations::MarkFinishedAnimations(base::TimeTicks monotonic_time) {
+  bool finished_transform_animation = false;
+  for (size_t i = 0; i < animations_.size(); ++i) {
+    if (!animations_[i]->is_finished() &&
+        animations_[i]->IsFinishedAt(monotonic_time)) {
+      animations_[i]->SetRunState(Animation::FINISHED, monotonic_time);
+      if (animations_[i]->target_property() == TargetProperty::TRANSFORM) {
+        finished_transform_animation = true;
+      }
+    }
+  }
+  if (finished_transform_animation)
+    UpdatePotentiallyAnimatingTransform();
+}
+
+void ElementAnimations::MarkAnimationsForDeletion(
+    base::TimeTicks monotonic_time,
+    AnimationEvents* events) {
+  bool marked_animations_for_deletions = false;
+  std::vector<size_t> animations_with_same_group_id;
+
+  animations_with_same_group_id.reserve(animations_.size());
+  // Non-aborted animations are marked for deletion after a corresponding
+  // AnimationEvent::FINISHED event is sent or received. This means that if
+  // we don't have an events vector, we must ensure that non-aborted animations
+  // have received a finished event before marking them for deletion.
+  for (size_t i = 0; i < animations_.size(); i++) {
+    int group_id = animations_[i]->group();
+    if (animations_[i]->run_state() == Animation::ABORTED) {
+      if (events && !animations_[i]->is_impl_only()) {
+        AnimationEvent aborted_event(
+            AnimationEvent::ABORTED, layer_id_, group_id,
+            animations_[i]->target_property(), monotonic_time);
+        events->events_.push_back(aborted_event);
+      }
+      // If on the compositor or on the main thread and received finish event,
+      // animation can be marked for deletion.
+      if (events || animations_[i]->received_finished_event()) {
+        animations_[i]->SetRunState(Animation::WAITING_FOR_DELETION,
+                                    monotonic_time);
+        marked_animations_for_deletions = true;
+      }
+      continue;
+    }
+
+    // If running on the compositor and need to complete an aborted animation
+    // on the main thread.
+    if (events &&
+        animations_[i]->run_state() ==
+            Animation::ABORTED_BUT_NEEDS_COMPLETION) {
+      AnimationEvent aborted_event(AnimationEvent::TAKEOVER, layer_id_,
+                                   group_id, animations_[i]->target_property(),
+                                   monotonic_time);
+      aborted_event.animation_start_time =
+          (animations_[i]->start_time() - base::TimeTicks()).InSecondsF();
+      const ScrollOffsetAnimationCurve* scroll_offset_animation_curve =
+          animations_[i]->curve()->ToScrollOffsetAnimationCurve();
+      aborted_event.curve = scroll_offset_animation_curve->Clone();
+      // Notify the compositor that the animation is finished.
+      NotifyPlayersAnimationFinished(aborted_event.monotonic_time,
+                                     aborted_event.target_property,
+                                     aborted_event.group_id);
+      // Notify main thread.
+      events->events_.push_back(aborted_event);
+
+      // Remove the animation from the compositor.
+      animations_[i]->SetRunState(Animation::WAITING_FOR_DELETION,
+                                  monotonic_time);
+      marked_animations_for_deletions = true;
+      continue;
+    }
+
+    bool all_anims_with_same_id_are_finished = false;
+
+    // Since deleting an animation on the main thread leads to its deletion
+    // on the impl thread, we only mark a FINISHED main thread animation for
+    // deletion once it has received a FINISHED event from the impl thread.
+    bool animation_i_will_send_or_has_received_finish_event =
+        animations_[i]->is_controlling_instance() ||
+        animations_[i]->is_impl_only() ||
+        animations_[i]->received_finished_event();
+    // If an animation is finished, and not already marked for deletion,
+    // find out if all other animations in the same group are also finished.
+    if (animations_[i]->run_state() == Animation::FINISHED &&
+        animation_i_will_send_or_has_received_finish_event) {
+      // Clear the animations_with_same_group_id if it was added for
+      // the previous animation's iteration.
+      if (animations_with_same_group_id.size() > 0)
+        animations_with_same_group_id.clear();
+      all_anims_with_same_id_are_finished = true;
+      for (size_t j = 0; j < animations_.size(); ++j) {
+        bool animation_j_will_send_or_has_received_finish_event =
+            animations_[j]->is_controlling_instance() ||
+            animations_[j]->is_impl_only() ||
+            animations_[j]->received_finished_event();
+        if (group_id == animations_[j]->group()) {
+          if (!animations_[j]->is_finished() ||
+              (animations_[j]->run_state() == Animation::FINISHED &&
+               !animation_j_will_send_or_has_received_finish_event)) {
+            all_anims_with_same_id_are_finished = false;
+            break;
+          } else if (j >= i &&
+                     animations_[j]->run_state() != Animation::ABORTED) {
+            // Mark down the animations which belong to the same group
+            // and is not yet aborted. If this current iteration finds that all
+            // animations with same ID are finished, then the marked
+            // animations below will be set to WAITING_FOR_DELETION in next
+            // iteration.
+            animations_with_same_group_id.push_back(j);
+          }
+        }
+      }
+    }
+    if (all_anims_with_same_id_are_finished) {
+      // We now need to remove all animations with the same group id as
+      // group_id (and send along animation finished notifications, if
+      // necessary).
+      for (size_t j = 0; j < animations_with_same_group_id.size(); j++) {
+        size_t animation_index = animations_with_same_group_id[j];
+        if (events) {
+          AnimationEvent finished_event(
+              AnimationEvent::FINISHED, layer_id_,
+              animations_[animation_index]->group(),
+              animations_[animation_index]->target_property(), monotonic_time);
+          finished_event.is_impl_only =
+              animations_[animation_index]->is_impl_only();
+          if (finished_event.is_impl_only)
+            NotifyAnimationFinished(finished_event);
+          else
+            events->events_.push_back(finished_event);
+        }
+        animations_[animation_index]->SetRunState(
+            Animation::WAITING_FOR_DELETION, monotonic_time);
+      }
+      marked_animations_for_deletions = true;
+    }
+  }
+  if (marked_animations_for_deletions)
+    NotifyObserversAnimationWaitingForDeletion();
+}
+
+void ElementAnimations::MarkAbortedAnimationsForDeletion(
+    ElementAnimations* element_animations_impl) const {
+  bool aborted_transform_animation = false;
+  auto& animations_impl = element_animations_impl->animations_;
+  for (const auto& animation_impl : animations_impl) {
+    // If the animation has been aborted on the main thread, mark it for
+    // deletion.
+    if (Animation* animation = GetAnimationById(animation_impl->id())) {
+      if (animation->run_state() == Animation::ABORTED) {
+        animation_impl->SetRunState(Animation::WAITING_FOR_DELETION,
+                                    element_animations_impl->last_tick_time_);
+        animation->SetRunState(Animation::WAITING_FOR_DELETION,
+                               last_tick_time_);
+        if (animation_impl->target_property() == TargetProperty::TRANSFORM) {
+          aborted_transform_animation = true;
+        }
+      }
+    }
+  }
+
+  if (aborted_transform_animation)
+    element_animations_impl->UpdatePotentiallyAnimatingTransform();
+}
+
+void ElementAnimations::PurgeAnimationsMarkedForDeletion() {
+  animations_.erase(
+      std::remove_if(animations_.begin(), animations_.end(),
+                     [](const std::unique_ptr<Animation>& animation) {
+                       return animation->run_state() ==
+                              Animation::WAITING_FOR_DELETION;
+                     }),
+      animations_.end());
+}
+
+void ElementAnimations::TickAnimations(base::TimeTicks monotonic_time) {
+  for (size_t i = 0; i < animations_.size(); ++i) {
+    if (animations_[i]->run_state() == Animation::STARTING ||
+        animations_[i]->run_state() == Animation::RUNNING ||
+        animations_[i]->run_state() == Animation::PAUSED) {
+      if (!animations_[i]->InEffect(monotonic_time))
+        continue;
+
+      base::TimeDelta trimmed =
+          animations_[i]->TrimTimeToCurrentIteration(monotonic_time);
+
+      switch (animations_[i]->target_property()) {
+        case TargetProperty::TRANSFORM: {
+          const TransformAnimationCurve* transform_animation_curve =
+              animations_[i]->curve()->ToTransformAnimationCurve();
+          const gfx::Transform transform =
+              transform_animation_curve->GetValue(trimmed);
+          NotifyObserversTransformAnimated(
+              transform, animations_[i]->affects_active_observers(),
+              animations_[i]->affects_pending_observers());
+          break;
+        }
+
+        case TargetProperty::OPACITY: {
+          const FloatAnimationCurve* float_animation_curve =
+              animations_[i]->curve()->ToFloatAnimationCurve();
+          const float opacity = std::max(
+              std::min(float_animation_curve->GetValue(trimmed), 1.0f), 0.f);
+          NotifyObserversOpacityAnimated(
+              opacity, animations_[i]->affects_active_observers(),
+              animations_[i]->affects_pending_observers());
+          break;
+        }
+
+        case TargetProperty::FILTER: {
+          const FilterAnimationCurve* filter_animation_curve =
+              animations_[i]->curve()->ToFilterAnimationCurve();
+          const FilterOperations filter =
+              filter_animation_curve->GetValue(trimmed);
+          NotifyObserversFilterAnimated(
+              filter, animations_[i]->affects_active_observers(),
+              animations_[i]->affects_pending_observers());
+          break;
+        }
+
+        case TargetProperty::BACKGROUND_COLOR: {
+          // Not yet implemented.
+          break;
+        }
+
+        case TargetProperty::SCROLL_OFFSET: {
+          const ScrollOffsetAnimationCurve* scroll_offset_animation_curve =
+              animations_[i]->curve()->ToScrollOffsetAnimationCurve();
+          const gfx::ScrollOffset scroll_offset =
+              scroll_offset_animation_curve->GetValue(trimmed);
+          NotifyObserversScrollOffsetAnimated(
+              scroll_offset, animations_[i]->affects_active_observers(),
+              animations_[i]->affects_pending_observers());
+          break;
+        }
+      }
+    }
+  }
+}
+
+void ElementAnimations::UpdateActivation(UpdateActivationType type) {
+  bool force = type == FORCE_ACTIVATION;
+  if (animation_host_) {
+    bool was_active = is_active_;
+    is_active_ = false;
+    for (size_t i = 0; i < animations_.size(); ++i) {
+      if (animations_[i]->run_state() != Animation::WAITING_FOR_DELETION) {
+        is_active_ = true;
+        break;
+      }
+    }
+
+    if (is_active_ && (!was_active || force))
+      animation_host_->DidActivateElementAnimations(this);
+    else if (!is_active_ && (was_active || force))
+      animation_host_->DidDeactivateElementAnimations(this);
+  }
+}
+
+void ElementAnimations::NotifyObserversOpacityAnimated(
+    float opacity,
+    bool notify_active_observers,
+    bool notify_pending_observers) {
+  if (notify_active_observers && needs_active_value_observations())
+    OnOpacityAnimated(LayerTreeType::ACTIVE, opacity);
+  if (notify_pending_observers && needs_pending_value_observations())
+    OnOpacityAnimated(LayerTreeType::PENDING, opacity);
+}
+
+void ElementAnimations::NotifyObserversTransformAnimated(
+    const gfx::Transform& transform,
+    bool notify_active_observers,
+    bool notify_pending_observers) {
+  if (notify_active_observers && needs_active_value_observations())
+    OnTransformAnimated(LayerTreeType::ACTIVE, transform);
+  if (notify_pending_observers && needs_pending_value_observations())
+    OnTransformAnimated(LayerTreeType::PENDING, transform);
+}
+
+void ElementAnimations::NotifyObserversFilterAnimated(
+    const FilterOperations& filters,
+    bool notify_active_observers,
+    bool notify_pending_observers) {
+  if (notify_active_observers && needs_active_value_observations())
+    OnFilterAnimated(LayerTreeType::ACTIVE, filters);
+  if (notify_pending_observers && needs_pending_value_observations())
+    OnFilterAnimated(LayerTreeType::PENDING, filters);
+}
+
+void ElementAnimations::NotifyObserversScrollOffsetAnimated(
+    const gfx::ScrollOffset& scroll_offset,
+    bool notify_active_observers,
+    bool notify_pending_observers) {
+  if (notify_active_observers && needs_active_value_observations())
+    OnScrollOffsetAnimated(LayerTreeType::ACTIVE, scroll_offset);
+  if (notify_pending_observers && needs_pending_value_observations())
+    OnScrollOffsetAnimated(LayerTreeType::PENDING, scroll_offset);
+}
+
+void ElementAnimations::NotifyObserversAnimationWaitingForDeletion() {
+  OnAnimationWaitingForDeletion();
+}
+
+void ElementAnimations::NotifyObserversTransformIsPotentiallyAnimatingChanged(
+    bool notify_active_observers,
+    bool notify_pending_observers) {
+  if (notify_active_observers && needs_active_value_observations())
+    OnTransformIsPotentiallyAnimatingChanged(
+        LayerTreeType::ACTIVE,
+        potentially_animating_transform_for_active_observers_);
+  if (notify_pending_observers && needs_pending_value_observations())
+    OnTransformIsPotentiallyAnimatingChanged(
+        LayerTreeType::PENDING,
+        potentially_animating_transform_for_pending_observers_);
+}
+
+void ElementAnimations::UpdatePotentiallyAnimatingTransform() {
+  bool was_potentially_animating_transform_for_active_observers =
+      potentially_animating_transform_for_active_observers_;
+  bool was_potentially_animating_transform_for_pending_observers =
+      potentially_animating_transform_for_pending_observers_;
+
+  potentially_animating_transform_for_active_observers_ = false;
+  potentially_animating_transform_for_pending_observers_ = false;
+
+  for (const auto& animation : animations_) {
+    if (!animation->is_finished() &&
+        animation->target_property() == TargetProperty::TRANSFORM) {
+      potentially_animating_transform_for_active_observers_ |=
+          animation->affects_active_observers();
+      potentially_animating_transform_for_pending_observers_ |=
+          animation->affects_pending_observers();
+    }
+  }
+
+  bool changed_for_active_observers =
+      was_potentially_animating_transform_for_active_observers !=
+      potentially_animating_transform_for_active_observers_;
+  bool changed_for_pending_observers =
+      was_potentially_animating_transform_for_pending_observers !=
+      potentially_animating_transform_for_pending_observers_;
+
+  if (!changed_for_active_observers && !changed_for_pending_observers)
+    return;
+
+  NotifyObserversTransformIsPotentiallyAnimatingChanged(
+      changed_for_active_observers, changed_for_pending_observers);
+}
+
+bool ElementAnimations::HasActiveAnimation() const {
+  for (size_t i = 0; i < animations_.size(); ++i) {
+    if (!animations_[i]->is_finished())
+      return true;
+  }
+  return false;
+}
+
+bool ElementAnimations::IsPotentiallyAnimatingProperty(
+    TargetProperty::Type target_property,
+    ObserverType observer_type) const {
+  for (size_t i = 0; i < animations_.size(); ++i) {
+    if (!animations_[i]->is_finished() &&
+        animations_[i]->target_property() == target_property) {
+      if ((observer_type == ObserverType::ACTIVE &&
+           animations_[i]->affects_active_observers()) ||
+          (observer_type == ObserverType::PENDING &&
+           animations_[i]->affects_pending_observers()))
+        return true;
+    }
+  }
+  return false;
+}
+
+bool ElementAnimations::IsCurrentlyAnimatingProperty(
+    TargetProperty::Type target_property,
+    ObserverType observer_type) const {
+  for (size_t i = 0; i < animations_.size(); ++i) {
+    if (!animations_[i]->is_finished() &&
+        animations_[i]->InEffect(last_tick_time_) &&
+        animations_[i]->target_property() == target_property) {
+      if ((observer_type == ObserverType::ACTIVE &&
+           animations_[i]->affects_active_observers()) ||
+          (observer_type == ObserverType::PENDING &&
+           animations_[i]->affects_pending_observers()))
+        return true;
+    }
+  }
+  return false;
 }
 
 void ElementAnimations::PauseAnimation(int animation_id,
                                        base::TimeDelta time_offset) {
-  layer_animation_controller_->PauseAnimation(animation_id, time_offset);
+  for (size_t i = 0; i < animations_.size(); ++i) {
+    if (animations_[i]->id() == animation_id) {
+      animations_[i]->SetRunState(Animation::PAUSED,
+                                  time_offset + animations_[i]->start_time() +
+                                      animations_[i]->time_offset());
+    }
+  }
 }
 
 void ElementAnimations::RemoveAnimation(int animation_id) {
-  layer_animation_controller_->RemoveAnimation(animation_id);
+  bool removed_transform_animation = false;
+  // Since we want to use the animations that we're going to remove, we need to
+  // use a stable_parition here instead of remove_if. Remove_if leaves the
+  // removed items in an unspecified state.
+  auto animations_to_remove = std::stable_partition(
+      animations_.begin(), animations_.end(),
+      [animation_id](const std::unique_ptr<Animation>& animation) {
+        return animation->id() != animation_id;
+      });
+  for (auto it = animations_to_remove; it != animations_.end(); ++it) {
+    if ((*it)->target_property() == TargetProperty::SCROLL_OFFSET) {
+      scroll_offset_animation_was_interrupted_ = true;
+    } else if ((*it)->target_property() == TargetProperty::TRANSFORM &&
+               !(*it)->is_finished()) {
+      removed_transform_animation = true;
+    }
+  }
+
+  animations_.erase(animations_to_remove, animations_.end());
+  UpdateActivation(NORMAL_ACTIVATION);
+  if (removed_transform_animation)
+    UpdatePotentiallyAnimatingTransform();
 }
 
 void ElementAnimations::AbortAnimation(int animation_id) {
-  layer_animation_controller_->AbortAnimation(animation_id);
+  bool aborted_transform_animation = false;
+  if (Animation* animation = GetAnimationById(animation_id)) {
+    if (!animation->is_finished()) {
+      animation->SetRunState(Animation::ABORTED, last_tick_time_);
+      if (animation->target_property() == TargetProperty::TRANSFORM)
+        aborted_transform_animation = true;
+    }
+  }
+  if (aborted_transform_animation)
+    UpdatePotentiallyAnimatingTransform();
 }
 
 void ElementAnimations::AbortAnimations(TargetProperty::Type target_property,
                                         bool needs_completion) {
-  layer_animation_controller_->AbortAnimations(target_property,
-                                               needs_completion);
+  if (needs_completion)
+    DCHECK(target_property == TargetProperty::SCROLL_OFFSET);
+
+  bool aborted_transform_animation = false;
+  for (size_t i = 0; i < animations_.size(); ++i) {
+    if (animations_[i]->target_property() == target_property &&
+        !animations_[i]->is_finished()) {
+      // Currently only impl-only scroll offset animations can be completed on
+      // the main thread.
+      if (needs_completion && animations_[i]->is_impl_only()) {
+        animations_[i]->SetRunState(Animation::ABORTED_BUT_NEEDS_COMPLETION,
+                                    last_tick_time_);
+      } else {
+        animations_[i]->SetRunState(Animation::ABORTED, last_tick_time_);
+      }
+      if (target_property == TargetProperty::TRANSFORM)
+        aborted_transform_animation = true;
+    }
+  }
+  if (aborted_transform_animation)
+    UpdatePotentiallyAnimatingTransform();
 }
 
 Animation* ElementAnimations::GetAnimation(
     TargetProperty::Type target_property) const {
-  return layer_animation_controller_->GetAnimation(target_property);
+  for (size_t i = 0; i < animations_.size(); ++i) {
+    size_t index = animations_.size() - i - 1;
+    if (animations_[index]->target_property() == target_property)
+      return animations_[index].get();
+  }
+  return nullptr;
 }
 
 Animation* ElementAnimations::GetAnimationById(int animation_id) const {
-  return layer_animation_controller_->GetAnimationById(animation_id);
+  for (size_t i = 0; i < animations_.size(); ++i)
+    if (animations_[i]->id() == animation_id)
+      return animations_[i].get();
+  return nullptr;
 }
 
 void ElementAnimations::OnFilterAnimated(LayerTreeType tree_type,
@@ -183,6 +1283,8 @@ void ElementAnimations::OnScrollOffsetAnimated(
 void ElementAnimations::OnAnimationWaitingForDeletion() {
   // TODO(loyso): Invalidate AnimationHost::SetNeedsPushProperties here.
   // But we always do PushProperties in AnimationHost for now. crbug.com/604280
+  DCHECK(animation_host());
+  animation_host()->OnAnimationWaitingForDeletion();
 }
 
 void ElementAnimations::OnTransformIsPotentiallyAnimatingChanged(
@@ -197,29 +1299,7 @@ void ElementAnimations::OnTransformIsPotentiallyAnimatingChanged(
                                                     is_animating);
 }
 
-void ElementAnimations::CreateActiveValueObserver() {
-  DCHECK(layer_animation_controller_);
-  DCHECK(!needs_active_value_observations());
-  layer_animation_controller_->set_needs_active_value_observations(true);
-}
-
-void ElementAnimations::DestroyActiveValueObserver() {
-  if (layer_animation_controller_)
-    layer_animation_controller_->set_needs_active_value_observations(false);
-}
-
-void ElementAnimations::CreatePendingValueObserver() {
-  DCHECK(layer_animation_controller_);
-  DCHECK(!needs_pending_value_observations());
-  layer_animation_controller_->set_needs_pending_value_observations(true);
-}
-
-void ElementAnimations::DestroyPendingValueObserver() {
-  if (layer_animation_controller_)
-    layer_animation_controller_->set_needs_pending_value_observations(false);
-}
-
-void ElementAnimations::NotifyAnimationStarted(
+void ElementAnimations::NotifyPlayersAnimationStarted(
     base::TimeTicks monotonic_time,
     TargetProperty::Type target_property,
     int group) {
@@ -230,7 +1310,7 @@ void ElementAnimations::NotifyAnimationStarted(
   }
 }
 
-void ElementAnimations::NotifyAnimationFinished(
+void ElementAnimations::NotifyPlayersAnimationFinished(
     base::TimeTicks monotonic_time,
     TargetProperty::Type target_property,
     int group) {
@@ -241,7 +1321,7 @@ void ElementAnimations::NotifyAnimationFinished(
   }
 }
 
-void ElementAnimations::NotifyAnimationAborted(
+void ElementAnimations::NotifyPlayersAnimationAborted(
     base::TimeTicks monotonic_time,
     TargetProperty::Type target_property,
     int group) {
@@ -252,7 +1332,7 @@ void ElementAnimations::NotifyAnimationAborted(
   }
 }
 
-void ElementAnimations::NotifyAnimationTakeover(
+void ElementAnimations::NotifyPlayersAnimationTakeover(
     base::TimeTicks monotonic_time,
     TargetProperty::Type target_property,
     double animation_start_time,
@@ -269,7 +1349,6 @@ void ElementAnimations::NotifyAnimationTakeover(
 }
 
 gfx::ScrollOffset ElementAnimations::ScrollOffsetForAnimation() const {
-  DCHECK(layer_animation_controller_);
   if (animation_host()) {
     DCHECK(animation_host()->mutator_host_client());
     return animation_host()->mutator_host_client()->GetScrollOffsetForAnimation(