ElementAnimations should hold an ObservableList of AnimationPlayers.

cc/test/animation_timelines_test_common.h

Index: cc/test/animation_timelines_test_common.h
diff --git a/cc/test/animation_timelines_test_common.h b/cc/test/animation_timelines_test_common.h
index 5470b693bf7723f403f79492b7d35518ee174e67..bcf632860564c2e7b3e1b1c40ef795029848c143 100644
--- a/cc/test/animation_timelines_test_common.h
+++ b/cc/test/animation_timelines_test_common.h
@@ -244,21 +244,21 @@ class TestAnimationDelegate : public AnimationDelegate {
                                double animation_start_time,
                                std::unique_ptr<AnimationCurve> curve) override;
 
-  bool started() { return started_; }
+  int started() { return started_; }
 
-  bool finished() { return finished_; }
+  int finished() { return finished_; }
 
-  bool aborted() { return aborted_; }
+  int aborted() { return aborted_; }
 
-  bool takeover() { return takeover_; }
+  int takeover() { return takeover_; }
 
   base::TimeTicks start_time() { return start_time_; }
 
  private:
-  bool started_;
-  bool finished_;
-  bool aborted_;
-  bool takeover_;
+  int started_;
+  int finished_;
+  int aborted_;
+  int takeover_;
   base::TimeTicks start_time_;
 };