ash: Use AnimationThroughputReporter for screen rotation metric

Bug: 1021774
Change-Id: I3e725eba1e129980470b1d361791d4eee099b682
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2266902Reviewed-by: Sammie Quon <sammiequon@chromium.org>
Commit-Queue: Xiyuan Xia <xiyuan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#782864}

ash/rotator/screen_rotation_animator.cc

@@ -8,6 +8,7 @@
 #include <utility>
 
 #include "ash/public/cpp/ash_switches.h"
+#include "ash/public/cpp/metrics_util.h"
 #include "ash/public/cpp/shell_window_ids.h"
 #include "ash/rotator/screen_rotation_animation.h"
 #include "ash/rotator/screen_rotation_animator_observer.h"
@@ -23,6 +24,7 @@
 #include "third_party/khronos/GLES2/gl2.h"
 #include "ui/aura/window.h"
 #include "ui/base/class_property.h"
+#include "ui/compositor/animation_throughput_reporter.h"
 #include "ui/compositor/callback_layer_animation_observer.h"
 #include "ui/compositor/layer.h"
 #include "ui/compositor/layer_animation_element.h"
@@ -183,20 +185,12 @@ ScreenRotationAnimator::ScreenRotationAnimator(aura::Window* root_window)
     : root_window_(root_window),
       screen_rotation_state_(IDLE),
       rotation_request_id_(0),
-      metrics_reporter_(std::make_unique<ui::HistogramPercentageMetricsReporter<
-                            kRotationAnimationSmoothness>>()),
       disable_animation_timers_for_test_(false) {}
 
 ScreenRotationAnimator::~ScreenRotationAnimator() {
   // To prevent a call to |AnimationEndedCallback()| from calling a method on
   // the |animator_|.
   weak_factory_.InvalidateWeakPtrs();
-
-  // Explicitly reset the |old_layer_tree_owner_| and |metrics_reporter_| in
-  // order to make sure |metrics_reporter_| outlives the attached animation
-  // sequence.
-  old_layer_tree_owner_.reset();
-  metrics_reporter_.reset();
 }
 
 void ScreenRotationAnimator::StartRotationAnimation(
@@ -462,8 +456,11 @@ void ScreenRotationAnimator::AnimateRotation(
       new_layer_animator->set_disable_timer_for_test(true);
     old_layer_animator->set_disable_timer_for_test(true);
   }
-  old_layer_animation_sequence->SetAnimationMetricsReporter(
-      metrics_reporter_.get());
+  ui::AnimationThroughputReporter reporter(
+      old_layer_animator,
+      metrics_util::ForSmoothness(base::BindRepeating([](int smoothness) {
+        UMA_HISTOGRAM_PERCENTAGE(kRotationAnimationSmoothness, smoothness);
+      })));
 
   // Add an observer so that the cloned/copied layers can be cleaned up with the
   // animation completes/aborts.

ash/rotator/screen_rotation_animator.h

@@ -27,7 +27,6 @@ class CopyOutputResult;
 }  // namespace cc
 
 namespace ui {
-class AnimationMetricsReporter;
 class LayerTreeOwner;
 class ScopedAnimationDurationScaleMode;
 }  // namespace ui
@@ -185,7 +184,6 @@ class ASH_EXPORT ScreenRotationAnimator {
   // cancel the previous rotation request.
   int64_t rotation_request_id_;
 
-  std::unique_ptr<ui::AnimationMetricsReporter> metrics_reporter_;
   // Only set in unittest to disable animation timers.
   bool disable_animation_timers_for_test_;
   base::ObserverList<ScreenRotationAnimatorObserver>::Unchecked