ElementAnimations should hold an ObservableList of AnimationPlayers.

cc/animation/animation_player.h

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CC_ANIMATION_ANIMATION_PLAYER_H_
 #define CC_ANIMATION_ANIMATION_PLAYER_H_
 
 #include <vector>
 
 #include "base/containers/linked_list.h"
@@ skipping 13 matching lines @@
 class ElementAnimations;
 
 // An AnimationPlayer owns all animations to be run on particular CC Layer.
 // Multiple AnimationPlayers can be attached to one layer. In this case,
 // they share common ElementAnimations so the
 // ElementAnimations-to-Layer relationship is 1:1.
 // For now, the blink logic is responsible for handling of conflicting
 // same-property animations.
 // Each AnimationPlayer has its copy on the impl thread.
 // This is a CC counterpart for blink::AnimationPlayer (in 1:1 relationship).
-class CC_EXPORT AnimationPlayer : public base::RefCounted<AnimationPlayer>,
-                                  public base::LinkNode<AnimationPlayer> {
+class CC_EXPORT AnimationPlayer : public base::RefCounted<AnimationPlayer> {
  public:
   static scoped_refptr<AnimationPlayer> Create(int id);
   scoped_refptr<AnimationPlayer> CreateImplInstance() const;
 
   int id() const { return id_; }
   ElementId element_id() const { return element_id_; }
 
   // Parent AnimationHost. AnimationPlayer can be detached from
   // AnimationTimeline.
   AnimationHost* animation_host() { return animation_host_; }
@@ skipping 22 matching lines @@
   void AddAnimation(std::unique_ptr<Animation> animation);
   void PauseAnimation(int animation_id, double time_offset);
   void RemoveAnimation(int animation_id);
   void AbortAnimation(int animation_id);
   void AbortAnimations(TargetProperty::Type target_property,
                        bool needs_completion);
 
   void PushPropertiesTo(AnimationPlayer* player_impl);
 
   // AnimationDelegate routing.
-  void NotifyAnimationStarted(base::TimeTicks monotonic_time,
-                              TargetProperty::Type target_property,
-                              int group);
-  void NotifyAnimationFinished(base::TimeTicks monotonic_time,
-                               TargetProperty::Type target_property,
-                               int group);
-  void NotifyAnimationAborted(base::TimeTicks monotonic_time,
-                              TargetProperty::Type target_property,
-                              int group);
-  void NotifyAnimationTakeover(base::TimeTicks monotonic_time,
-                               TargetProperty::Type target_property,
-                               double animation_start_time,
-                               std::unique_ptr<AnimationCurve> curve);
+  virtual void OnAnimationStarted(base::TimeTicks monotonic_time,

[loyso (OOO), 2016/08/04 06:32:10]

It's very sad to make it polymorphic only for the sake of testing purposes.

[loyso (OOO), 2016/08/04 06:50:37]

I'm severely jet lagged but... Can we use
AnimationPlayer::set_animation_delegate in tests?

[ymalik, 2016/08/04 15:31:47]

Yes, I am detaching the player from the timeline from TestAnimationDelegate.
This way we don't have to make this polymorphic. Thanks.

+                                  TargetProperty::Type target_property,
+                                  int group);
+  virtual void OnAnimationFinished(base::TimeTicks monotonic_time,
+                                   TargetProperty::Type target_property,
+                                   int group);
+  virtual void OnAnimationAborted(base::TimeTicks monotonic_time,
+                                  TargetProperty::Type target_property,
+                                  int group);
+  virtual void OnAnimationTakeover(base::TimeTicks monotonic_time,
+                                   TargetProperty::Type target_property,
+                                   double animation_start_time,
+                                   std::unique_ptr<AnimationCurve> curve);
 
   // Whether this player has animations waiting to get sent to ElementAnimations
   bool has_pending_animations_for_testing() const {
     return !animations_.empty();
   }
 
+ protected:
+  explicit AnimationPlayer(int id);
+  virtual ~AnimationPlayer();
+
  private:
   friend class base::RefCounted<AnimationPlayer>;
 
-  explicit AnimationPlayer(int id);
-  ~AnimationPlayer();
-
   void SetNeedsCommit();
 
   void RegisterPlayer();
   void UnregisterPlayer();
 
   void BindElementAnimations();
   void UnbindElementAnimations();
 
   // We accumulate added animations in animations_ container
   // if element_animations_ is a nullptr. It allows us to add/remove animations
   // to non-attached AnimationPlayers.
   std::vector<std::unique_ptr<Animation>> animations_;
 
   AnimationHost* animation_host_;
   AnimationTimeline* animation_timeline_;
   // element_animations isn't null if player attached to an element (layer).
   scoped_refptr<ElementAnimations> element_animations_;
   AnimationDelegate* animation_delegate_;
 
   int id_;
   ElementId element_id_;
 
   DISALLOW_COPY_AND_ASSIGN(AnimationPlayer);
 };
 
 }  // namespace cc
 
 #endif  // CC_ANIMATION_ANIMATION_PLAYER_H_