[animations] Adds metrics for jank on selected layer animations

ui/compositor/layer_animation_sequence.h

 // Copyright (c) 2012 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 UI_COMPOSITOR_LAYER_ANIMATION_SEQUENCE_H_
 #define UI_COMPOSITOR_LAYER_ANIMATION_SEQUENCE_H_
 
 #include <stddef.h>
 
 #include <memory>
@@ skipping 109 matching lines @@
   void OnThreadedAnimationStarted(base::TimeTicks monotonic_time,
                                   cc::TargetProperty::Type target_property,
                                   int group_id);
 
   // Called when the animator schedules this sequence.
   void OnScheduled();
 
   // Called when the animator is destroyed.
   void OnAnimatorDestroyed();
 
+  // Sets |animation_metrics_reporter_| and passes it to all |elements_|.
+  void SetAnimationMetricsReporter(AnimationMetricsReporter* reporter);
+
   // The last_progressed_fraction of the element most recently progressed by
   // by this sequence. Returns 0.0 if no elements have been progressed.
   double last_progressed_fraction() const { return last_progressed_fraction_; }
 
   size_t size() const;
 
   LayerAnimationElement* FirstElement() const;
 
  private:
   friend class LayerAnimatorTestController;
@@ skipping 44 matching lines @@
   // group id.
   int animation_group_id_;
 
   // These parties are notified when layer animations end.
   base::ObserverList<LayerAnimationObserver> observers_;
 
   // Tracks the last_progressed_fraction() of the most recently progressed
   // element.
   double last_progressed_fraction_;
 
+  // Used to tag animation elements to obtain metrics of animation performance.
+  AnimationMetricsReporter* animation_metrics_reporter_;
+
   base::WeakPtrFactory<LayerAnimationSequence> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(LayerAnimationSequence);
 };
 
 }  // namespace ui
 
 #endif  // UI_COMPOSITOR_LAYER_ANIMATION_SEQUENCE_H_