Assistant: Add UMA for container view animation

This patch adds UMA to measure assistant container view's animation
smoothness.

Bug: b/113942916, 887583
Test: see UMA in histograms.
Change-Id: I83da71c4c0003061f5ca852a6128534a681646d3
Reviewed-on: https://chromium-review.googlesource.com/1234956Reviewed-by: Steven Holte <holte@chromium.org>
Reviewed-by: Xiaohui Chen <xiaohuic@chromium.org>
Commit-Queue: Tao Wu <wutao@chromium.org>
Cr-Commit-Position: refs/heads/master@{#593411}

ash/assistant/ui/assistant_container_view.cc

@@ -15,6 +15,7 @@
 #include "ash/assistant/ui/assistant_web_view.h"
 #include "ash/shell.h"
 #include "base/logging.h"
+#include "base/metrics/histogram_macros.h"
 #include "base/strings/utf_string_conversions.h"
 #include "ui/aura/window.h"
 #include "ui/aura/window_targeter.h"
@@ -144,13 +145,24 @@ class AssistantContainerLayout : public views::LayoutManager {
   DISALLOW_COPY_AND_ASSIGN(AssistantContainerLayout);
 };
 
+int GetCompositorFrameNumber(ui::Layer* layer) {
+  ui::Compositor* compositor = layer->GetCompositor();
+  return compositor ? compositor->activated_frame_count() : 0;
+}
+
+float GetCompositorRefreshRate(ui::Layer* layer) {
+  ui::Compositor* compositor = layer->GetCompositor();
+  return compositor ? compositor->refresh_rate() : 60.0f;
+}
+
 }  // namespace
 
 // AssistantContainerView ------------------------------------------------------
 
 AssistantContainerView::AssistantContainerView(
     AssistantController* assistant_controller)
-    : assistant_controller_(assistant_controller) {
+    : assistant_controller_(assistant_controller),
+      animation_start_frame_number_(0) {
   set_accept_events(true);
   SetAnchor(nullptr);
   set_close_on_deactivate(false);
@@ -234,6 +246,8 @@ void AssistantContainerView::PreferredSizeChanged() {
     radius_start_ =
         GetBubbleFrameView()->bubble_border()->GetBorderCornerRadius();
 
+    animation_start_frame_number_ = GetCompositorFrameNumber(layer());
+
     // Start animation.
     resize_animation_->Show();
     return;
@@ -392,6 +406,27 @@ void AssistantContainerView::AnimationProgressed(
   GetWidget()->SetBounds(bounds);
 }
 
+void AssistantContainerView::AnimationEnded(const gfx::Animation* animation) {
+  const int ideal_frames = GetCompositorRefreshRate(layer()) *
+                           kResizeAnimationDurationMs /
+                           base::Time::kMillisecondsPerSecond;
+
+  const int actual_frames =
+      GetCompositorFrameNumber(layer()) - animation_start_frame_number_;
+  if (actual_frames <= 0)
+    return;
+
+  int smoothness = 100;
+  // The |actual_frames| could be |ideal_frames| + 1. The reason could be that
+  // the animation timer is running with interval of 0.016666 s, which could
+  // animate one more frame than expected due to rounding error.
+  if (ideal_frames > actual_frames)
+    smoothness = 100 * actual_frames / ideal_frames;
+
+  UMA_HISTOGRAM_PERCENTAGE("Assistant.ContainerView.Resize.AnimationSmoothness",
+                           smoothness);
+}
+
 void AssistantContainerView::OnDisplayMetricsChanged(
     const display::Display& display,
     uint32_t changed_metrics) {

ash/assistant/ui/assistant_container_view.h

@@ -62,6 +62,7 @@ class AssistantContainerView : public views::BubbleDialogDelegateView,
 
   // gfx::AnimationDelegate:
   void AnimationProgressed(const gfx::Animation* animation) override;
+  void AnimationEnded(const gfx::Animation* animation) override;
 
   // display::DisplayObserver:
   void OnDisplayMetricsChanged(const display::Display& display,
@@ -101,6 +102,8 @@ class AssistantContainerView : public views::BubbleDialogDelegateView,
   // This layer shows a rounded rectangle with drop shadow.
   ui::Layer shadow_layer_;
 
+  int animation_start_frame_number_ = 0;
+
   DISALLOW_COPY_AND_ASSIGN(AssistantContainerView);
 };
 

tools/metrics/histograms/histograms.xml

@@ -5205,6 +5205,16 @@ uploading your change for review.
   </summary>
 </histogram>
 
+<histogram name="Assistant.ContainerView.Resize.AnimationSmoothness" units="%">
+  <owner>wutao@chromium.org</owner>
+  <summary>
+    Relative animation smoothness of resizing assistant container window. 100%
+    represents ideally smooth 60 frames per second. 50% represents when only 30
+    frames per second is achieved during the animations. 0% should not happen.
+    This metric is recorded when the container window resizing is finished.
+  </summary>
+</histogram>
+
 <histogram name="Assistant.HotwordEnableNotification" enum="BooleanHit">
   <owner>updowndota@chromium.org</owner>
   <summary>