WIP: Plumbing input event latency reporting through Mus GPU.

content/browser/renderer_host/input/render_widget_host_latency_tracker.h

 // Copyright 2014 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_
 
 #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"
+#include "ui/latency/latency_tracker.h"
 
 namespace content {
 
 class RenderWidgetHostDelegate;
 
 // Utility class for tracking the latency of events passing through
 // a given RenderWidgetHost.
-class CONTENT_EXPORT RenderWidgetHostLatencyTracker {
+class CONTENT_EXPORT RenderWidgetHostLatencyTracker
+    : NON_EXPORTED_BASE(public ui::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,
@@ skipping 12 matching lines @@
   // 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);
 
-  // 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);
-
   // 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*);
 
  private:
+  // ui::LatencyTracker:
+  void ReportRapporScrollLatency(
+      const std::string& name,
+      const ui::LatencyInfo::LatencyComponent& start_component,
+      const ui::LatencyInfo::LatencyComponent& end_component) override;
+
   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_;
 
   RenderWidgetHostDelegate* render_widget_host_delegate_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderWidgetHostLatencyTracker);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_INPUT_RENDER_WIDGET_HOST_LATENCY_TRACKER_H_