Ash HUD: Cleanup code of the "FPS" graph tab.

This CL refactors the animations frame rate graph
simplifying data acquisition.

Bug: 1075612
Change-Id: Icc0ed230f08cc561423e0b49881cebe67f7b7a11
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2538702Reviewed-by: Mitsuru Oshima <oshima@chromium.org>
Commit-Queue: Alexander Alekseev <alemate@chromium.org>
Cr-Commit-Position: refs/heads/master@{#835711}

ash/BUILD.gn

@@ -510,8 +510,6 @@ component("ash") {
     "host/root_window_transformer.h",
     "host/transformer_helper.cc",
     "host/transformer_helper.h",
-    "hud_display/compositor_stats.cc",
-    "hud_display/compositor_stats.h",
     "hud_display/cpu_graph_page_view.cc",
     "hud_display/cpu_graph_page_view.h",
     "hud_display/cpu_status.cc",

ash/hud_display/compositor_stats.cc

-// Copyright 2020 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.
-
-#include "ash/hud_display/compositor_stats.h"
-
-#include "ui/compositor/compositor.h"
-#include "ui/gfx/presentation_feedback.h"
-
-namespace ash {
-namespace hud_display {
-
-CompositorStats::CompositorStats() = default;
-CompositorStats::~CompositorStats() = default;
-
-void CompositorStats::OnDidPresentCompositorFrame(
-    const gfx::PresentationFeedback& feedback) {
-  constexpr base::TimeDelta kOneSec = base::TimeDelta::FromSeconds(1);
-  constexpr base::TimeDelta k500ms = base::TimeDelta::FromMilliseconds(500);
-  if (!feedback.failed())
-    presented_times_.push_back(feedback.timestamp);
-
-  const base::TimeTicks deadline_1s = feedback.timestamp - kOneSec;
-  while (!presented_times_.empty() && presented_times_.front() <= deadline_1s)
-    presented_times_.pop_front();
-
-  const base::TimeTicks deadline_500ms = feedback.timestamp - k500ms;
-  frame_rate_for_last_half_second_ = 0;
-  for (auto i = presented_times_.crbegin();
-       (i != presented_times_.crend()) && (*i > deadline_500ms); ++i) {
-    ++frame_rate_for_last_half_second_;
-  }
-  frame_rate_for_last_half_second_ *= 2;
-}
-
-}  // namespace hud_display
-}  // namespace ash

ash/hud_display/compositor_stats.h

-// Copyright 2020 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 ASH_HUD_DISPLAY_COMPOSITOR_STATS_H_
-#define ASH_HUD_DISPLAY_COMPOSITOR_STATS_H_
-
-#include "base/containers/circular_deque.h"
-#include "base/time/time.h"
-
-namespace gfx {
-struct PresentationFeedback;
-}
-
-namespace ash {
-namespace hud_display {
-
-class CompositorStats {
- public:
-  CompositorStats();
-  CompositorStats(const CompositorStats&) = delete;
-  CompositorStats& operator=(const CompositorStats&) = delete;
-  ~CompositorStats();
-
-  float frame_rate_for_last_second() const { return presented_times_.size(); }
-
-  float frame_rate_for_last_half_second() const {
-    return frame_rate_for_last_half_second_;
-  }
-
-  // Updates the stats with |feedback|.
-  void OnDidPresentCompositorFrame(const gfx::PresentationFeedback& feedback);
-
- private:
-  float frame_rate_for_last_half_second_;
-
-  // |timestamp| from PresentationFeedback for one second.
-  base::circular_deque<base::TimeTicks> presented_times_;
-};
-
-}  // namespace hud_display
-}  // namespace ash
-
-#endif  // ASH_HUD_DISPLAY_COMPOSITOR_STATS_H_

ash/hud_display/fps_graph_page_view.cc

@@ -15,6 +15,7 @@
 #include "base/strings/utf_string_conversions.h"
 #include "ui/aura/window_tree_host.h"
 #include "ui/gfx/canvas.h"
+#include "ui/gfx/presentation_feedback.h"
 #include "ui/views/metadata/metadata_impl_macros.h"
 #include "ui/views/widget/widget.h"
 
@@ -111,9 +112,10 @@ void FPSGraphPageView::OnPaint(gfx::Canvas* canvas) {
 void FPSGraphPageView::OnDidPresentCompositorFrame(
     uint32_t frame_token,
     const gfx::PresentationFeedback& feedback) {
-  compositor_stats_.OnDidPresentCompositorFrame(feedback);
-  float frame_rate_1s = compositor_stats_.frame_rate_for_last_second();
-  float frame_rate_500ms = compositor_stats_.frame_rate_for_last_half_second();
+  UpdateStats(feedback);
+
+  float frame_rate_1s = frame_rate_for_last_second();
+  float frame_rate_500ms = frame_rate_for_last_half_second();
 
   float refresh_rate = GetWidget()->GetCompositor()->refresh_rate();
 
@@ -160,6 +162,25 @@ void FPSGraphPageView::OnWindowRemovingFromRootWindow(aura::Window* window,
   }
 }
 
+void FPSGraphPageView::UpdateStats(const gfx::PresentationFeedback& feedback) {
+  constexpr base::TimeDelta kOneSec = base::TimeDelta::FromSeconds(1);
+  constexpr base::TimeDelta k500ms = base::TimeDelta::FromMilliseconds(500);
+  if (!feedback.failed())
+    presented_times_.push_back(feedback.timestamp);
+
+  const base::TimeTicks deadline_1s = feedback.timestamp - kOneSec;
+  while (!presented_times_.empty() && presented_times_.front() <= deadline_1s)
+    presented_times_.pop_front();
+
+  const base::TimeTicks deadline_500ms = feedback.timestamp - k500ms;
+  frame_rate_for_last_half_second_ = 0;
+  for (auto i = presented_times_.crbegin();
+       (i != presented_times_.crend()) && (*i > deadline_500ms); ++i) {
+    ++frame_rate_for_last_half_second_;
+  }
+  frame_rate_for_last_half_second_ *= 2;
+}
+
 void FPSGraphPageView::UpdateTopLabel(float refresh_rate) {
   const float refresh_rate_rounded_10 =
       ceilf(unsigned(refresh_rate) / 10.0F) * 10;

ash/hud_display/fps_graph_page_view.h

@@ -7,22 +7,25 @@
 
 #include "time.h"
 
-#include "ash/hud_display/compositor_stats.h"
 #include "ash/hud_display/graph.h"
 #include "ash/hud_display/graph_page_view_base.h"
+#include "base/containers/circular_deque.h"
 #include "ui/aura/window_observer.h"
 #include "ui/compositor/compositor_observer.h"
 #include "ui/views/view_observer.h"
 
+namespace gfx {
+struct PresentationFeedback;
+}
+
 namespace ash {
 namespace hud_display {
 
 class Grid;
 
-// Draws FPS graphs.
-// Graph is updated in two ways:
-// 1. Regular update with UpdateData() sifts graph and adds new point.
-// 2. Every time OnFramePresented() is called, the last graph value is updated.
+// Draws several graphs per UI compositor frame.  Every time
+// OnDidPresentCompositorFrame() is called a new value is appended to the end
+// of the graph. Every time UpdateData() is called, legend values are updated.
 class FPSGraphPageView : public GraphPageViewBase,
                          public ui::CompositorObserver,
                          public views::ViewObserver,
@@ -53,9 +56,18 @@ class FPSGraphPageView : public GraphPageViewBase,
                                       aura::Window* new_root) override;
 
  private:
+  float frame_rate_for_last_second() const { return presented_times_.size(); }
+
+  float frame_rate_for_last_half_second() const {
+    return frame_rate_for_last_half_second_;
+  }
+
   // Sets grid top label to the maximum of the observed refresh rate.
   void UpdateTopLabel(float f_refresh_rate);
 
+  // Updates the stats with |feedback|.
+  void UpdateStats(const gfx::PresentationFeedback& feedback);
+
   // Number of frames per second presented.
   Graph frame_rate_1s_;
   Graph frame_rate_500ms_;
@@ -65,7 +77,10 @@ class FPSGraphPageView : public GraphPageViewBase,
 
   Grid* grid_;  // not owned
 
-  CompositorStats compositor_stats_;
+  float frame_rate_for_last_half_second_;
+
+  // |timestamp| from PresentationFeedback for one second.
+  base::circular_deque<base::TimeTicks> presented_times_;
 };
 
 }  // namespace hud_display