Adds UMA for screen rotation animation smoothness.

Adding histgram of screen rotation animation smoothness.

BUG=678763
TEST=manual, created histogram locally.

Review-Url: https://codereview.chromium.org/2771713004
Cr-Commit-Position: refs/heads/master@{#459635}

ash/rotator/screen_rotation_animator.cc

@@ -14,9 +14,11 @@
 #include "ash/shell.h"
 #include "base/command_line.h"
 #include "base/memory/ptr_util.h"
+#include "base/metrics/histogram_macros.h"
 #include "base/time/time.h"
 #include "ui/aura/window.h"
 #include "ui/compositor/layer.h"
+#include "ui/compositor/layer_animation_element.h"
 #include "ui/compositor/layer_animation_observer.h"
 #include "ui/compositor/layer_animation_sequence.h"
 #include "ui/compositor/layer_animator.h"
@@ -143,15 +145,15 @@ LayerCleanupObserver::~LayerCleanupObserver() {
 void LayerCleanupObserver::OnLayerAnimationEnded(
     ui::LayerAnimationSequence* sequence) {
   if (animator_)
-    animator_->OnLayerAnimationEnded();
+    animator_->ProcessAnimationQueue();
 
   delete this;
 }
 
 void LayerCleanupObserver::OnLayerAnimationAborted(
     ui::LayerAnimationSequence* sequence) {
   if (animator_)
-    animator_->OnLayerAnimationAborted();
+    animator_->ProcessAnimationQueue();
 
   delete this;
 }
@@ -167,6 +169,20 @@ void LayerCleanupObserver::OnDetachedFromSequence(
   sequence_ = nullptr;
 }
 
+class ScreenRotationAnimationMetricsReporter
+    : public ui::AnimationMetricsReporter {
+ public:
+  ScreenRotationAnimationMetricsReporter() {}
+  ~ScreenRotationAnimationMetricsReporter() override {}
+
+  void Report(int value) override {
+    UMA_HISTOGRAM_PERCENTAGE("Ash.Rotation.AnimationSmoothness", value);
+  }
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(ScreenRotationAnimationMetricsReporter);
+};
+
 }  // namespace
 
 struct ScreenRotationAnimator::ScreenRotationRequest {
@@ -180,10 +196,22 @@ struct ScreenRotationAnimator::ScreenRotationRequest {
 ScreenRotationAnimator::ScreenRotationAnimator(int64_t display_id)
     : display_id_(display_id),
       is_rotating_(false),
+      metrics_reporter_(
+          base::MakeUnique<ScreenRotationAnimationMetricsReporter>()),
       disable_animation_timers_for_test_(false),
       weak_factory_(this) {}
 
-ScreenRotationAnimator::~ScreenRotationAnimator() {}
+ScreenRotationAnimator::~ScreenRotationAnimator() {
+  // To prevent a call to |LayerCleanupObserver::OnLayerAnimationAborted()| 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::AnimateRotation(
     std::unique_ptr<ScreenRotationRequest> rotation_request) {
@@ -278,6 +306,7 @@ void ScreenRotationAnimator::AnimateRotation(
   // control the animation.
   if (disable_animation_timers_for_test_)
     animator->set_disable_timer_for_test(true);
+  animation_sequence->SetAnimationMetricsReporter(metrics_reporter_.get());
   animator->StartAnimation(animation_sequence.release());
 
   rotation_request.reset();
@@ -313,15 +342,6 @@ void ScreenRotationAnimator::RemoveScreenRotationAnimatorObserver(
   screen_rotation_animator_observers_.RemoveObserver(observer);
 }
 
-void ScreenRotationAnimator::OnLayerAnimationEnded() {
-  ProcessAnimationQueue();
-}
-
-void ScreenRotationAnimator::OnLayerAnimationAborted() {
-  AbortAnimations(old_layer_tree_owner_->root());
-  ProcessAnimationQueue();
-}
-
 void ScreenRotationAnimator::ProcessAnimationQueue() {
   is_rotating_ = false;
   old_layer_tree_owner_.reset();

ash/rotator/screen_rotation_animator.h

@@ -14,6 +14,7 @@
 #include "ui/display/display.h"
 
 namespace ui {
+class AnimationMetricsReporter;
 class Layer;
 class LayerTreeOwner;
 }  // namespace ui
@@ -49,9 +50,10 @@ class ASH_EXPORT ScreenRotationAnimator {
   void RemoveScreenRotationAnimatorObserver(
       ScreenRotationAnimatorObserver* observer);
 
-  void OnLayerAnimationEnded();
-
-  void OnLayerAnimationAborted();
+  // When screen rotation animation is ended or aborted, calls |Rotate()| with
+  // the pending rotation request if the request queue is not empty. Otherwise
+  // notifies |screen_rotation_animator_observer_|.
+  void ProcessAnimationQueue();
 
  private:
   friend class ash::test::ScreenRotationAnimatorTestApi;
@@ -64,18 +66,14 @@ class ASH_EXPORT ScreenRotationAnimator {
   // |rotation_degrees| arc.
   void AnimateRotation(std::unique_ptr<ScreenRotationRequest> rotation_request);
 
-  // When screen rotation animation is ended or aborted, if the request queue is
-  // not empty, it will call |Rotate()| with the pending rotation request.
-  // Otherwise it will notify |screen_rotation_animator_observer_|.
-  void ProcessAnimationQueue();
-
   void set_disable_animation_timers_for_test(bool disable_timers);
 
   void StopAnimating();
 
   // The id of the display to rotate.
   int64_t display_id_;
   bool is_rotating_;
+  std::unique_ptr<ui::AnimationMetricsReporter> metrics_reporter_;
   // Only set in unittest to disable animation timers.
   bool disable_animation_timers_for_test_;
   base::ObserverList<ScreenRotationAnimatorObserver>

tools/metrics/histograms/histograms.xml

@@ -1877,6 +1877,16 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="Ash.Rotation.AnimationSmoothness" units="%">
+  <owner>wutao@chromium.org</owner>
+  <summary>
+    Relative smoothness of animations when rotating screen. 100% represents
+    ideally smooth 60 frames per second. 50% represents only 30 frames per
+    second is achieved during the animations. 0% should not happen. This metric
+    is recorded exactly once when the user rotates the screen.
+  </summary>
+</histogram>
+
 <histogram name="Ash.Shelf.Menu.NumItemsEnabledUponSelection" units="Count">
   <owner>bruthig@google.com</owner>
   <owner>tdanderson@google.com</owner>