content/browser/renderer_host/render_widget_host_latency_tracker.h

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_LATENCY_TRACKER_H_
   6 #define CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_LATENCY_TRACKER_H_
   7
   8 #include <vector>
   9
  10 #include "base/basictypes.h"
  11 #include "cc/base/rolling_time_delta_history.h"
  12 #include "content/browser/renderer_host/event_with_latency_info.h"
  13 #include "content/common/content_export.h"
  14 #include "ui/events/latency_info.h"
  15
  16 namespace content {
  17
  18 // Utility class for tracking the latency of events passing through
  19 // a given RenderWidgetHost.
  20 class CONTENT_EXPORT RenderWidgetHostLatencyTracker {
  21  public:
  22   RenderWidgetHostLatencyTracker();
  23   ~RenderWidgetHostLatencyTracker();
  24
  25   // Associates the latency tracker with a given route and process.
  26   // Called once after the RenderWidgetHost is fully initialized.
  27   void Initialize(int routing_id, int process_id);
  28
  29   // Populates the LatencyInfo with relevant entries for latency tracking.
  30   // Called when an event is received by the RenderWidgetHost, prior to
  31   // that event being forwarded to the renderer (via the InputRouter).
  32   void OnInputEvent(const blink::WebInputEvent& event,
  33                     ui::LatencyInfo* latency);
  34
  35   // Populates the LatencyInfo with relevant entries for latency tracking, also
  36   // terminating latency tracking for events that did not trigger rendering and
  37   // performing relevant UMA latency reporting. Called when an event is ack'ed
  38   // to the RenderWidgetHost (from the InputRouter).
  39   void OnInputEventAck(const blink::WebInputEvent& event,
  40                        ui::LatencyInfo* latency);
  41
  42   // Populates renderer-created LatencyInfo entries with the appropriate latency
  43   // component id. Called when the RenderWidgetHost receives a compositor swap
  44   // update from the renderer.
  45   void OnSwapCompositorFrame(std::vector<ui::LatencyInfo>* latencies);
  46
  47   // Terminates latency tracking for events that triggered rendering, also
  48   // performing relevant UMA latency reporting.
  49   // Called when the RenderWidgetHost receives a swap update from the GPU.
  50   void OnFrameSwapped(const ui::LatencyInfo& latency);
  51
  52   // Produces an estimate of the time between browser composite and GPU swap,
  53   // as informed by historical latency values.
  54   base::TimeDelta GetEstimatedBrowserCompositeTime() const;
  55
  56   // WebInputEvent coordinates are in DPIs, while LatencyInfo expects
  57   // coordinates in device pixels.
  58   void set_device_scale_factor(float device_scale_factor) {
  59     device_scale_factor_ = device_scale_factor;
  60   }
  61
  62   // Returns the ID that uniquely describes this component to the latency
  63   // subsystem.
  64   int64 latency_component_id() const { return latency_component_id_; }
  65
  66  private:
  67   int64 last_event_id_;
  68   int64 latency_component_id_;
  69   float device_scale_factor_;
  70   bool has_seent_first_gesture_scroll_update_;
  71   cc::RollingTimeDeltaHistory browser_composite_latency_history_;
  72
  73   DISALLOW_COPY_AND_ASSIGN(RenderWidgetHostLatencyTracker);
  74 };
  75
  76 }  // namespace content
  77
  78 #endif  // CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_LATENCY_TRACKER_H_