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