Plumbing input event latency reporting through Mus GPU.

ui/latency/latency_tracker.h

-// Copyright 2014 The Chromium Authors. All rights reserved.
+// Copyright 2017 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 CONTENT_BROWSER_RENDERER_HOST_INPUT_RENDER_WIDGET_HOST_LATENCY_TRACKER_H_
-#define CONTENT_BROWSER_RENDERER_HOST_INPUT_RENDER_WIDGET_HOST_LATENCY_TRACKER_H_
+#ifndef UI_LATENCY_LATENCY_TRACKER_H_
+#define UI_LATENCY_LATENCY_TRACKER_H_
 
 #include <stdint.h>
 
 #include <vector>
 
 #include "base/macros.h"
-#include "content/browser/renderer_host/event_with_latency_info.h"
-#include "content/common/content_export.h"
-#include "content/common/input/input_event_ack_state.h"
 #include "ui/latency/latency_info.h"
 
-namespace content {
+namespace ui {
 
-class RenderWidgetHostDelegate;
-
-// Utility class for tracking the latency of events passing through
-// a given RenderWidgetHost.
-class CONTENT_EXPORT RenderWidgetHostLatencyTracker {
+// Utility class for tracking the latency of events.
+class LatencyTracker {
  public:
-  explicit RenderWidgetHostLatencyTracker();
-  ~RenderWidgetHostLatencyTracker();
-
-  // Associates the latency tracker with a given route and process.
-  // Called once after the RenderWidgetHost is fully initialized.
-  void Initialize(int routing_id, int process_id);
-
-  void ComputeInputLatencyHistograms(blink::WebInputEvent::Type type,
-                                     int64_t latency_component_id,
-                                     const ui::LatencyInfo& latency,
-                                     InputEventAckState ack_result);
-
-  // Populates the LatencyInfo with relevant entries for latency tracking.
-  // Called when an event is received by the RenderWidgetHost, prior to
-  // that event being forwarded to the renderer (via the InputRouter).
-  void OnInputEvent(const blink::WebInputEvent& event,
-                    ui::LatencyInfo* latency);
-
-  // Populates the LatencyInfo with relevant entries for latency tracking, also
-  // terminating latency tracking for events that did not trigger rendering and
-  // performing relevant UMA latency reporting. Called when an event is ack'ed
-  // to the RenderWidgetHost (from the InputRouter).
-  void OnInputEventAck(const blink::WebInputEvent& event,
-                       ui::LatencyInfo* latency,
-                       InputEventAckState ack_result);
-
-  // Populates renderer-created LatencyInfo entries with the appropriate latency
-  // component id. Called when the RenderWidgetHost receives a compositor swap
-  // update from the renderer.
-  void OnSwapCompositorFrame(std::vector<ui::LatencyInfo>* latencies);
+  LatencyTracker() = default;
+  ~LatencyTracker() = default;
 
   // Terminates latency tracking for events that triggered rendering, also
   // performing relevant UMA latency reporting.
-  // Called when the RenderWidgetHost receives a swap update from the GPU.
-  void OnGpuSwapBuffersCompleted(const ui::LatencyInfo& latency);
+  // Called when GPU buffers swap completes.
+  void OnGpuSwapBuffersCompleted(const LatencyInfo& latency);
 
-  // WebInputEvent coordinates are in DPIs, while LatencyInfo expects
-  // coordinates in device pixels.
-  void set_device_scale_factor(float device_scale_factor) {
-    device_scale_factor_ = device_scale_factor;
-  }
-
-  // Returns the ID that uniquely describes this component to the latency
-  // subsystem.
-  int64_t latency_component_id() const { return latency_component_id_; }
-
-  // A delegate is used to get the url to be stored in Rappor Sample.
-  // If delegate is null no Rappor sample will be reported.
-  void SetDelegate(RenderWidgetHostDelegate*);
+ protected:
+  virtual void ReportRapporScrollLatency(
+      const std::string& name,
+      const LatencyInfo::LatencyComponent& start_component,
+      const LatencyInfo::LatencyComponent& end_component);
 
  private:
-  int64_t last_event_id_;
-  int64_t latency_component_id_;
-  float device_scale_factor_;
-  bool has_seen_first_gesture_scroll_update_;
-  // Whether the current stream of touch events includes more than one active
-  // touch point. This is set in OnInputEvent, and cleared in OnInputEventAck.
-  bool active_multi_finger_gesture_;
-  // Whether the touch start for the current stream of touch events had its
-  // default action prevented. Only valid for single finger gestures.
-  bool touch_start_default_prevented_;
+  void ComputeTouchAndWheelScrollLatencyHistograms(
+      const LatencyInfo::LatencyComponent& gpu_swap_begin_component,
+      const LatencyInfo::LatencyComponent& gpu_swap_end_component,
+      const LatencyInfo& latency);
 
-  RenderWidgetHostDelegate* render_widget_host_delegate_;
-
-  DISALLOW_COPY_AND_ASSIGN(RenderWidgetHostLatencyTracker);
+  DISALLOW_COPY_AND_ASSIGN(LatencyTracker);
 };
 
-}  // namespace content
+}  // namespace latency
 
-#endif  // CONTENT_BROWSER_RENDERER_HOST_INPUT_RENDER_WIDGET_HOST_LATENCY_TRACKER_H_
+#endif  // UI_LATENCY_LATENCY_TRACKER_H_