content/browser/renderer_host/event_with_latency_info.h

   1 // Copyright 2013 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_EVENT_WITH_LATENCY_INFO_H_
   6 #define CONTENT_BROWSER_RENDERER_HOST_EVENT_WITH_LATENCY_INFO_H_
   7
   8 #include "ui/events/latency_info.h"
   9
  10 #include "content/common/input/web_input_event_traits.h"
  11 #include "content/public/browser/native_web_keyboard_event.h"
  12
  13 namespace blink {
  14 class WebGestureEvent;
  15 class WebMouseEvent;
  16 class WebMouseWheelEvent;
  17 class WebTouchEvent;
  18 }
  19
  20 namespace content {
  21
  22 template <typename T>
  23 class EventWithLatencyInfo {
  24  public:
  25   T event;
  26   mutable ui::LatencyInfo latency;
  27
  28   explicit EventWithLatencyInfo(const T& e) : event(e) {}
  29
  30   EventWithLatencyInfo(const T& e, const ui::LatencyInfo& l)
  31       : event(e), latency(l) {}
  32
  33   EventWithLatencyInfo() {}
  34
  35   bool CanCoalesceWith(const EventWithLatencyInfo& other)
  36       const WARN_UNUSED_RESULT {
  37     return WebInputEventTraits::CanCoalesce(other.event, event);
  38   }
  39
  40   void CoalesceWith(const EventWithLatencyInfo& other) {
  41     // |other| should be a newer event than |this|.
  42     if (other.latency.trace_id() >= 0 && latency.trace_id() >= 0)
  43       DCHECK_GT(other.latency.trace_id(), latency.trace_id());
  44     double old_timestamp = event.timeStampSeconds;
  45     WebInputEventTraits::Coalesce(other.event, &event);
  46     // When coalescing two input events, we keep the oldest LatencyInfo
  47     // for Telemetry latency test since it will represent the longest
  48     // latency.
  49     if (other.latency.trace_id() >= 0 &&
  50         (latency.trace_id() < 0 ||
  51          other.latency.trace_id() < latency.trace_id())) {
  52       latency = other.latency;
  53     }
  54     latency.AddCoalescedEventTimestamp(old_timestamp);
  55   }
  56 };
  57
  58 typedef EventWithLatencyInfo<NativeWebKeyboardEvent>
  59     NativeWebKeyboardEventWithLatencyInfo;
  60 typedef EventWithLatencyInfo<blink::WebGestureEvent>
  61     GestureEventWithLatencyInfo;
  62 typedef EventWithLatencyInfo<blink::WebMouseWheelEvent>
  63     MouseWheelEventWithLatencyInfo;
  64 typedef EventWithLatencyInfo<blink::WebMouseEvent>
  65     MouseEventWithLatencyInfo;
  66 typedef EventWithLatencyInfo<blink::WebTouchEvent>
  67     TouchEventWithLatencyInfo;
  68
  69 }  // namespace content
  70
  71 #endif  // CONTENT_BROWSER_RENDERER_HOST_EVENT_WITH_LATENCY_INFO_H_