Clean up LatencyInfo and RWHLatencyTracker.

content/browser/renderer_host/input/render_widget_host_latency_tracker.cc

 // 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.
 
 #include "content/browser/renderer_host/input/render_widget_host_latency_tracker.h"
 
 #include <stddef.h>
 
 #include "base/logging.h"
 #include "base/metrics/histogram_macros.h"
@@ skipping 57 matching lines @@
                                  latency, device_scale_factor);
   } else if (WebInputEvent::isTouchEventType(event.type)) {
     UpdateLatencyCoordinatesImpl(static_cast<const WebTouchEvent&>(event),
                                  latency, device_scale_factor);
   } else if (event.type == WebInputEvent::MouseWheel) {
     UpdateLatencyCoordinatesImpl(static_cast<const WebMouseWheelEvent&>(event),
                                  latency, device_scale_factor);
   }
 }
 
-// Touch to scroll latency that is mostly under 1 second.
-#define UMA_HISTOGRAM_TOUCH_TO_SCROLL_LATENCY(name, start, end)               \
-  UMA_HISTOGRAM_CUSTOM_COUNTS(                                                \
-      name, (end.event_time - start.event_time).InMicroseconds(), 1, 1000000, \
-      100)
+// Check valid timing for start and end latency components.
+#define CONFIRM_VALID_TIMING(start, end)     \
+  DCHECK(!start.first_event_time.is_null()); \
+  DCHECK(!end.last_event_time.is_null());    \
+  DCHECK_GE(end.last_event_time, start.first_event_time);
+
+// Event latency that is mostly under 1 second. We should only use 100 buckets
+// when needed.
+#define UMA_HISTOGRAM_INPUT_LATENCY_HIGH_RESOLUTION_MICROSECONDS(name, start, \
+                                                                 end)         \
+  CONFIRM_VALID_TIMING(start, end)                                            \
+  base::Histogram::FactoryGet(name, 1, 1000000, 100,                          \
+                              base::HistogramBase::kUmaTargetedHistogramFlag) \
+      ->Add((end.last_event_time - start.first_event_time).InMicroseconds());

[Ilya Sherman, 2016/12/15 23:14:49]

What's the reason that you're switching away from histogram macros?  And, if
you're switching away from histogram macros, what's the reason to keep the outer
macros?

FWIW, base::Histogram::FactoryGet is less thread-safe than the UMA macros.  And,
if you do want to skip the macro, I'd recommend using the wrappers provided in
histogram_functions.h.

[tdresser, 2016/12/16 13:48:53]

The reason to not use the standard macros is that we're creating the names
dynamically, which makes this code _way_ more readable.

The reason to not use the histogram_functions.h calls is the performance
penalty. I'm trying to find something which isn't much slower than the previous
approach, but lets me get rid of the lines and lines of hard to read repetitive
histogram macros.

We're calling these macros a bunch of times per event. I see a few approaches to
dealing with this, for example:
https://cs.chromium.org/chromium/src/ui/events/event.cc?rcl=0&l=67

[Ilya Sherman, 2016/12/17 01:25:21]

Is this a measured performance penalty?  If so, what was the observed penalty? 
I'm surprised that you'd see much difference between calling FactoryGet()
directly and using histogram_functions.h.
If you really care about performance, then you should probably sacrifice
readability in favor of using the most performant macros, which are the ones
defined in histogram_macros.h.  These macros allocate a static pointer, which is
what gives them the performance boost.  It's also what makes them incompatible
with runtime-variable names.

+
+#define UMA_HISTOGRAM_INPUT_LATENCY_MILLISECONDS(name, start, end)            \
+  CONFIRM_VALID_TIMING(start, end)                                            \
+  base::Histogram::FactoryGet(name, 1, 1000, 50,                              \
+                              base::HistogramBase::kUmaTargetedHistogramFlag) \
+      ->Add((end.last_event_time - start.first_event_time).InMilliseconds());
 
 // Long scroll latency component that is mostly under 200ms.
 #define UMA_HISTOGRAM_SCROLL_LATENCY_LONG(name, start, end)        \
   UMA_HISTOGRAM_CUSTOM_COUNTS(                                     \
     name,                                                          \
     (end.event_time - start.event_time).InMicroseconds(),          \
     1000, 200000, 50)
 
 // Short scroll latency component that is mostly under 50ms.
 #define UMA_HISTOGRAM_SCROLL_LATENCY_SHORT(name, start, end)       \
   UMA_HISTOGRAM_CUSTOM_COUNTS(                                     \
     name,                                                          \
     (end.event_time - start.event_time).InMicroseconds(),          \
     1, 50000, 50)
 
-// Check valid timing for start and end latency components.
-#define CONFIRM_VALID_TIMING(start, end)     \
-  DCHECK(!start.first_event_time.is_null()); \
-  DCHECK(!end.last_event_time.is_null());    \
-  DCHECK_GE(end.last_event_time, start.first_event_time);
-
-// Touch/wheel to scroll latency that is mostly under 1 second.
-#define UMA_HISTOGRAM_TOUCH_WHEEL_TO_SCROLL_LATENCY(name, start, end)         \
-  CONFIRM_VALID_TIMING(start, end)                                            \
-  base::Histogram::FactoryGet(name, 1, 1000000, 100,                          \
-                              base::HistogramBase::kUmaTargetedHistogramFlag) \
-      ->Add((end.last_event_time - start.first_event_time).InMicroseconds());
-
 // Long touch/wheel scroll latency component that is mostly under 200ms.
 #define UMA_HISTOGRAM_SCROLL_LATENCY_LONG_2(name, start, end)                 \
   CONFIRM_VALID_TIMING(start, end)                                            \
   base::Histogram::FactoryGet(name, 1000, 200000, 50,                         \
                               base::HistogramBase::kUmaTargetedHistogramFlag) \
       ->Add((end.last_event_time - start.first_event_time).InMicroseconds());
 
 // Short touch/wheel scroll latency component that is mostly under 50ms.
 #define UMA_HISTOGRAM_SCROLL_LATENCY_SHORT_2(name, start, end)                \
   CONFIRM_VALID_TIMING(start, end)                                            \
   base::Histogram::FactoryGet(name, 1, 50000, 50,                             \
                               base::HistogramBase::kUmaTargetedHistogramFlag) \
       ->Add((end.last_event_time - start.first_event_time).InMicroseconds());
 
+std::string LatencySourceEventTypeToInputModalityString(
+    ui::SourceEventType type) {
+  switch (type) {
+    case ui::SourceEventType::WHEEL:
+      return "Wheel";
+    case ui::SourceEventType::TOUCH:
+      return "Touch";
+    default:
+      return "";
+  }
+}
+
+std::string WebInputEventTypeToInputModalityString(WebInputEvent::Type type) {
+  if (type == blink::WebInputEvent::MouseWheel) {
+    return "Wheel";
+  } else if (WebInputEvent::isKeyboardEventType(type)) {
+    return "Key";
+  } else if (WebInputEvent::isMouseEventType(type)) {
+    return "Mouse";
+  } else if (WebInputEvent::isTouchEventType(type)) {
+    return "Touch";
+  }
+  return "";
+}
+
 void ComputeScrollLatencyHistograms(
     const LatencyInfo::LatencyComponent& gpu_swap_begin_component,
     const LatencyInfo::LatencyComponent& gpu_swap_end_component,
     int64_t latency_component_id,
     const LatencyInfo& latency,
     bool is_running_navigation_hint_task) {
   DCHECK(!latency.coalesced());
   if (latency.coalesced())
     return;
 
   DCHECK(!gpu_swap_begin_component.event_time.is_null());
   DCHECK(!gpu_swap_end_component.event_time.is_null());
   LatencyInfo::LatencyComponent original_component;
   if (latency.FindLatency(
           ui::INPUT_EVENT_LATENCY_FIRST_SCROLL_UPDATE_ORIGINAL_COMPONENT,
           latency_component_id, &original_component)) {
     // This UMA metric tracks the time between the final frame swap for the
     // first scroll event in a sequence and the original timestamp of that
     // scroll event's underlying touch event.
     for (size_t i = 0; i < original_component.event_count; i++) {
-      UMA_HISTOGRAM_TOUCH_TO_SCROLL_LATENCY(
+      UMA_HISTOGRAM_INPUT_LATENCY_HIGH_RESOLUTION_MICROSECONDS(
           "Event.Latency.TouchToFirstScrollUpdateSwapBegin",
           original_component, gpu_swap_begin_component);
     }
     // TODO(horo): IsRunningNavigationHintTask UMAs are only for
     // SpeculativeLaunchServiceWorker experimentation. So remove this UMA when
     // the experimentation finished (crbug.com/638827).
     if (is_running_navigation_hint_task) {
       for (size_t i = 0; i < original_component.event_count; i++) {
-        UMA_HISTOGRAM_TOUCH_TO_SCROLL_LATENCY(
+        UMA_HISTOGRAM_INPUT_LATENCY_HIGH_RESOLUTION_MICROSECONDS(
             "Event.Latency.TouchToFirstScrollUpdateSwapBegin_"
             "IsRunningNavigationHintTask",
             original_component, gpu_swap_begin_component);
       }
     }
   } else if (!latency.FindLatency(
                  ui::INPUT_EVENT_LATENCY_SCROLL_UPDATE_ORIGINAL_COMPONENT,
                  latency_component_id, &original_component)) {
     return;
   }
 
   // This UMA metric tracks the time from when the original touch event is
   // created to when the scroll gesture results in final frame swap.
   for (size_t i = 0; i < original_component.event_count; i++) {
-    UMA_HISTOGRAM_TOUCH_TO_SCROLL_LATENCY(
+    UMA_HISTOGRAM_INPUT_LATENCY_HIGH_RESOLUTION_MICROSECONDS(
         "Event.Latency.TouchToScrollUpdateSwapBegin", original_component,
         gpu_swap_begin_component);
   }
   // TODO(horo): IsRunningNavigationHintTask UMAs are only for
   // SpeculativeLaunchServiceWorker experimentation. So remove this UMA when
   // the experimentation finished (crbug.com/638827).
   if (is_running_navigation_hint_task) {
     for (size_t i = 0; i < original_component.event_count; i++) {
-      UMA_HISTOGRAM_TOUCH_TO_SCROLL_LATENCY(
+      UMA_HISTOGRAM_INPUT_LATENCY_HIGH_RESOLUTION_MICROSECONDS(
           "Event.Latency.TouchToScrollUpdateSwapBegin_"
           "IsRunningNavigationHintTask",
           original_component, gpu_swap_begin_component);
     }
   }
 
   // TODO(miletus): Add validation for making sure the following components
   // are present and their event times are legit.
   LatencyInfo::LatencyComponent rendering_scheduled_component;
   bool rendering_scheduled_on_main = latency.FindLatency(
@@ skipping 49 matching lines @@
   UMA_HISTOGRAM_SCROLL_LATENCY_SHORT("Event.Latency.ScrollUpdate.GpuSwap",
                                      gpu_swap_begin_component,
                                      gpu_swap_end_component);
 }
 
 void ComputeTouchAndWheelScrollLatencyHistograms(
     RenderWidgetHostDelegate* render_widget_host_delegate,
     const ui::LatencyInfo::LatencyComponent& gpu_swap_begin_component,
     const ui::LatencyInfo::LatencyComponent& gpu_swap_end_component,
     int64_t latency_component_id,
-    const ui::LatencyInfo& latency,
-    const std::string event_type_name) {
+    const ui::LatencyInfo& latency) {
   DCHECK(!latency.coalesced());
   if (latency.coalesced())
     return;
 
   LatencyInfo::LatencyComponent original_component;
   std::string scroll_name = "ScrollUpdate";
+
+  const std::string input_modality =
+      LatencySourceEventTypeToInputModalityString(latency.source_event_type());
+
   if (latency.FindLatency(
           ui::INPUT_EVENT_LATENCY_FIRST_SCROLL_UPDATE_ORIGINAL_COMPONENT,
           latency_component_id, &original_component)) {
     scroll_name = "ScrollBegin";
     // This UMA metric tracks the time between the final frame swap for the
     // first scroll event in a sequence and the original timestamp of that
     // scroll event's underlying touch/wheel event.
-
-    UMA_HISTOGRAM_TOUCH_WHEEL_TO_SCROLL_LATENCY(
-        "Event.Latency.ScrollBegin." + event_type_name +
+    UMA_HISTOGRAM_INPUT_LATENCY_HIGH_RESOLUTION_MICROSECONDS(
+        "Event.Latency.ScrollBegin." + input_modality +
             ".TimeToScrollUpdateSwapBegin2",
         original_component, gpu_swap_begin_component);
 
     // TODO(lanwei): Will remove them when M56 is stable, see
     // https://crbug.com/669618.
-    UMA_HISTOGRAM_TOUCH_WHEEL_TO_SCROLL_LATENCY(
-        "Event.Latency.ScrollUpdate." + event_type_name +
+    UMA_HISTOGRAM_INPUT_LATENCY_HIGH_RESOLUTION_MICROSECONDS(
+        "Event.Latency.ScrollUpdate." + input_modality +
             ".TimeToFirstScrollUpdateSwapBegin2",
         original_component, gpu_swap_begin_component);
   } else if (latency.FindLatency(
                  ui::INPUT_EVENT_LATENCY_SCROLL_UPDATE_ORIGINAL_COMPONENT,
                  latency_component_id, &original_component)) {
     // This UMA metric tracks the time from when the original touch event is
     // created to when the scroll gesture results in final frame swap.
     // First scroll events are excluded from this metric.
-    if (event_type_name == "Touch") {
-      UMA_HISTOGRAM_TOUCH_WHEEL_TO_SCROLL_LATENCY(
-          "Event.Latency.ScrollUpdate." + event_type_name +
-              ".TimeToScrollUpdateSwapBegin2",
+    if (input_modality == "Touch") {
+      UMA_HISTOGRAM_INPUT_LATENCY_HIGH_RESOLUTION_MICROSECONDS(
+          "Event.Latency.ScrollUpdate.Touch.TimeToScrollUpdateSwapBegin2",
           original_component, gpu_swap_begin_component);
 
       rappor::RapporService* rappor_service =
           GetContentClient()->browser()->GetRapporService();
       if (rappor_service && render_widget_host_delegate) {
         std::unique_ptr<rappor::Sample> sample =
             rappor_service->CreateSample(rappor::UMA_RAPPOR_TYPE);
         render_widget_host_delegate->AddDomainInfoToRapporSample(sample.get());
         sample->SetUInt64Field("Latency",
                                (gpu_swap_begin_component.last_event_time -
@@ skipping 17 matching lines @@
   if (!rendering_scheduled_on_main) {
     if (!latency.FindLatency(
             ui::INPUT_EVENT_LATENCY_RENDERING_SCHEDULED_IMPL_COMPONENT, 0,
             &rendering_scheduled_component))
       return;
   }
 
   const std::string thread_name = rendering_scheduled_on_main ? "Main" : "Impl";
 
   UMA_HISTOGRAM_SCROLL_LATENCY_LONG_2(
-      "Event.Latency." + scroll_name + "." + event_type_name +
+      "Event.Latency." + scroll_name + "." + input_modality +
           ".TimeToHandled2_" + thread_name,
       original_component, rendering_scheduled_component);
 
   LatencyInfo::LatencyComponent renderer_swap_component;
   if (!latency.FindLatency(ui::INPUT_EVENT_LATENCY_RENDERER_SWAP_COMPONENT, 0,
                            &renderer_swap_component))
     return;
 
   UMA_HISTOGRAM_SCROLL_LATENCY_LONG_2(
-      "Event.Latency." + scroll_name + "." + event_type_name +
+      "Event.Latency." + scroll_name + "." + input_modality +
           ".HandledToRendererSwap2_" + thread_name,
       rendering_scheduled_component, renderer_swap_component);
 
   LatencyInfo::LatencyComponent browser_received_swap_component;
   if (!latency.FindLatency(
           ui::INPUT_EVENT_BROWSER_RECEIVED_RENDERER_SWAP_COMPONENT, 0,
           &browser_received_swap_component))
     return;
 
   UMA_HISTOGRAM_SCROLL_LATENCY_SHORT_2(
-      "Event.Latency." + scroll_name + "." + event_type_name +
+      "Event.Latency." + scroll_name + "." + input_modality +
           ".RendererSwapToBrowserNotified2",
       renderer_swap_component, browser_received_swap_component);
 
   UMA_HISTOGRAM_SCROLL_LATENCY_LONG_2(
-      "Event.Latency." + scroll_name + "." + event_type_name +
+      "Event.Latency." + scroll_name + "." + input_modality +
           ".BrowserNotifiedToBeforeGpuSwap2",
       browser_received_swap_component, gpu_swap_begin_component);
 
   UMA_HISTOGRAM_SCROLL_LATENCY_SHORT_2(
-      "Event.Latency." + scroll_name + "." + event_type_name + ".GpuSwap2",
+      "Event.Latency." + scroll_name + "." + input_modality + ".GpuSwap2",
       gpu_swap_begin_component, gpu_swap_end_component);
 }
 // LatencyComponents generated in the renderer must have component IDs
 // provided to them by the browser process. This function adds the correct
 // component ID where necessary.
 void AddLatencyInfoComponentIds(LatencyInfo* latency,
                                 int64_t latency_component_id) {
   std::vector<std::pair<ui::LatencyComponentType, int64_t>> new_components_key;
   std::vector<LatencyInfo::LatencyComponent> new_components_value;
   for (const auto& lc : latency->latency_components()) {
@@ skipping 39 matching lines @@
   DCHECK_EQ(0, latency_component_id_);
   last_event_id_ = static_cast<int64_t>(process_id) << 32;
   latency_component_id_ = routing_id | last_event_id_;
 }
 
 void RenderWidgetHostLatencyTracker::ComputeInputLatencyHistograms(
     WebInputEvent::Type type,
     int64_t latency_component_id,
     const LatencyInfo& latency,
     InputEventAckState ack_result) {
+  // If this event was coalesced into another event, ignore it, as the event it
+  // was coalesced into will reflect the full latency.
   if (latency.coalesced())
     return;
 
+  if (type != blink::WebInputEvent::MouseWheel &&
+      !WebInputEvent::isTouchEventType(type)) {
+    return;
+  }
+
   LatencyInfo::LatencyComponent rwh_component;
   if (!latency.FindLatency(ui::INPUT_EVENT_LATENCY_BEGIN_RWH_COMPONENT,
                            latency_component_id, &rwh_component)) {
     return;
   }
   DCHECK_EQ(rwh_component.event_count, 1u);
 
   LatencyInfo::LatencyComponent ui_component;
   if (latency.FindLatency(ui::INPUT_EVENT_LATENCY_UI_COMPONENT, 0,
                           &ui_component)) {
     DCHECK_EQ(ui_component.event_count, 1u);
     base::TimeDelta ui_delta =
-        rwh_component.event_time - ui_component.event_time;
+        rwh_component.last_event_time - ui_component.first_event_time;
 
     if (type == blink::WebInputEvent::MouseWheel) {
       UMA_HISTOGRAM_CUSTOM_COUNTS("Event.Latency.Browser.WheelUI",
                                   ui_delta.InMicroseconds(), 1, 20000, 100);
-
     } else {
       DCHECK(WebInputEvent::isTouchEventType(type));
       UMA_HISTOGRAM_CUSTOM_COUNTS("Event.Latency.Browser.TouchUI",
                                   ui_delta.InMicroseconds(), 1, 20000, 100);
     }
   }
 
   // Both tap and scroll gestures depend on the disposition of the touch start
   // and the current touch. For touch start, touch_start_default_prevented_ ==
   // (ack_result == INPUT_EVENT_ACK_STATE_CONSUMED).
   bool action_prevented = touch_start_default_prevented_ ||
                           ack_result == INPUT_EVENT_ACK_STATE_CONSUMED;
 
+  std::string event_name = WebInputEvent::GetName(type);
+
+  std::string default_action_status =
+      action_prevented ? "DefaultPrevented" : "DefaultAllowed";
+
   LatencyInfo::LatencyComponent main_component;
   if (latency.FindLatency(ui::INPUT_EVENT_LATENCY_RENDERER_MAIN_COMPONENT, 0,
                           &main_component)) {
     DCHECK_EQ(main_component.event_count, 1u);
-    base::TimeDelta queueing_delta =
-        main_component.event_time - rwh_component.event_time;
-
     if (!multi_finger_gesture_) {
-      if (action_prevented) {
-        switch (type) {
-          case WebInputEvent::TouchStart:
-            UMA_HISTOGRAM_TIMES(
-              "Event.Latency.QueueingTime.TouchStartDefaultPrevented",
-              queueing_delta);
-            break;
-          case WebInputEvent::TouchMove:
-            UMA_HISTOGRAM_TIMES(
-                "Event.Latency.QueueingTime.TouchMoveDefaultPrevented",
-                queueing_delta);
-            break;
-          case WebInputEvent::TouchEnd:
-            UMA_HISTOGRAM_TIMES(
-                "Event.Latency.QueueingTime.TouchEndDefaultPrevented",
-                queueing_delta);
-            break;
-          default:
-            break;
-        }
-      } else {
-        switch (type) {
-          case WebInputEvent::TouchStart:
-            UMA_HISTOGRAM_TIMES(
-                "Event.Latency.QueueingTime.TouchStartDefaultAllowed",
-                queueing_delta);
-            break;
-          case WebInputEvent::TouchMove:
-            UMA_HISTOGRAM_TIMES(
-                "Event.Latency.QueueingTime.TouchMoveDefaultAllowed",
-                queueing_delta);
-            break;
-          case WebInputEvent::TouchEnd:
-            UMA_HISTOGRAM_TIMES(
-                "Event.Latency.QueueingTime.TouchEndDefaultAllowed",
-                queueing_delta);
-            break;
-          default:
-            break;
-        }
-      }
+      UMA_HISTOGRAM_INPUT_LATENCY_MILLISECONDS(
+          "Event.Latency.QueueingTime." + event_name + default_action_status,
+          rwh_component, main_component);
     }
   }
 
   LatencyInfo::LatencyComponent acked_component;
   if (latency.FindLatency(ui::INPUT_EVENT_LATENCY_ACK_RWH_COMPONENT, 0,
                           &acked_component)) {
     DCHECK_EQ(acked_component.event_count, 1u);
-    base::TimeDelta acked_delta =
-        acked_component.event_time - rwh_component.event_time;
-    if (type == blink::WebInputEvent::MouseWheel) {
-      UMA_HISTOGRAM_CUSTOM_COUNTS("Event.Latency.Browser.WheelAcked",
-                                  acked_delta.InMicroseconds(), 1, 1000000,
-                                  100);
-    } else {
-      DCHECK(WebInputEvent::isTouchEventType(type));
-      UMA_HISTOGRAM_CUSTOM_COUNTS("Event.Latency.Browser.TouchAcked",
-                                  acked_delta.InMicroseconds(), 1, 1000000,
-                                  100);
+    if (!multi_finger_gesture_ &&
+        main_component.event_time != base::TimeTicks()) {
+      UMA_HISTOGRAM_INPUT_LATENCY_MILLISECONDS(
+          "Event.Latency.BlockingTime." + event_name + default_action_status,
+          main_component, acked_component);
     }
 
-    if (!multi_finger_gesture_ &&
-        main_component.event_time != base::TimeTicks()) {
-      base::TimeDelta blocking_delta;
-      blocking_delta = acked_component.event_time - main_component.event_time;
-
-      if (action_prevented) {
-        switch (type) {
-          case WebInputEvent::TouchStart:
-            UMA_HISTOGRAM_TIMES(
-                "Event.Latency.BlockingTime.TouchStartDefaultPrevented",
-                blocking_delta);
-            break;
-          case WebInputEvent::TouchMove:
-            UMA_HISTOGRAM_TIMES(
-                "Event.Latency.BlockingTime.TouchMoveDefaultPrevented",
-                blocking_delta);
-            break;
-          case WebInputEvent::TouchEnd:
-            UMA_HISTOGRAM_TIMES(
-                "Event.Latency.BlockingTime.TouchEndDefaultPrevented",
-                blocking_delta);
-            break;
-          default:
-            break;
-        }
-      } else {
-        switch (type) {
-          case WebInputEvent::TouchStart:
-            UMA_HISTOGRAM_TIMES(
-                "Event.Latency.BlockingTime.TouchStartDefaultAllowed",
-                blocking_delta);
-            break;
-          case WebInputEvent::TouchMove:
-            UMA_HISTOGRAM_TIMES(
-                "Event.Latency.BlockingTime.TouchMoveDefaultAllowed",
-                blocking_delta);
-            break;
-          case WebInputEvent::TouchEnd:
-            UMA_HISTOGRAM_TIMES(
-                "Event.Latency.BlockingTime.TouchEndDefaultAllowed",
-                blocking_delta);
-            break;
-          default:
-            break;
-        }
-      }
+    std::string input_modality = WebInputEventTypeToInputModalityString(type);
+    if (input_modality != "") {
+      UMA_HISTOGRAM_INPUT_LATENCY_HIGH_RESOLUTION_MICROSECONDS(
+          "Event.Latency.Browser." + input_modality + "Acked", rwh_component,
+          acked_component);
     }
   }
 }
 
 void RenderWidgetHostLatencyTracker::OnInputEvent(
     const blink::WebInputEvent& event,
     LatencyInfo* latency) {
   DCHECK(latency);
   if (latency->FindLatency(ui::INPUT_EVENT_LATENCY_BEGIN_RWH_COMPONENT,
                            latency_component_id_, NULL)) {
@@ skipping 53 matching lines @@
     const blink::WebInputEvent& event,
     LatencyInfo* latency, InputEventAckState ack_result) {
   DCHECK(latency);
 
   // Latency ends when it is acked but does not cause render scheduling.
   bool rendering_scheduled = latency->FindLatency(
       ui::INPUT_EVENT_LATENCY_RENDERING_SCHEDULED_MAIN_COMPONENT, 0, nullptr);
   rendering_scheduled |= latency->FindLatency(
       ui::INPUT_EVENT_LATENCY_RENDERING_SCHEDULED_IMPL_COMPONENT, 0, nullptr);
 
-  if (WebInputEvent::isGestureEventType(event.type)) {
-    if (!rendering_scheduled) {
-      latency->AddLatencyNumber(
-          ui::INPUT_EVENT_LATENCY_TERMINATED_GESTURE_COMPONENT, 0, 0);
-      // TODO(jdduke): Consider exposing histograms for gesture event types.
-    }
-    return;
-  }
-
   if (WebInputEvent::isTouchEventType(event.type)) {
     const WebTouchEvent& touch_event =
         *static_cast<const WebTouchEvent*>(&event);
     if (event.type == WebInputEvent::TouchStart) {
       DCHECK(touch_event.touchesLength >= 1);
       multi_finger_gesture_ = touch_event.touchesLength != 1;
       touch_start_default_prevented_ =
           ack_result == INPUT_EVENT_ACK_STATE_CONSUMED;
     }
-
-    latency->AddLatencyNumber(ui::INPUT_EVENT_LATENCY_ACK_RWH_COMPONENT, 0, 0);
-
-    if (!rendering_scheduled) {
-      latency->AddLatencyNumber(
-          ui::INPUT_EVENT_LATENCY_TERMINATED_TOUCH_COMPONENT, 0, 0);
-    }
-    ComputeInputLatencyHistograms(event.type, latency_component_id_, *latency,
-                                  ack_result);
-    return;
   }
 
-  if (event.type == WebInputEvent::MouseWheel) {
-    latency->AddLatencyNumber(ui::INPUT_EVENT_LATENCY_ACK_RWH_COMPONENT, 0, 0);
-    if (!rendering_scheduled) {
-      latency->AddLatencyNumber(
-          ui::INPUT_EVENT_LATENCY_TERMINATED_MOUSE_WHEEL_COMPONENT, 0, 0);
-    }
-    ComputeInputLatencyHistograms(event.type, latency_component_id_, *latency,
-                                  ack_result);
-    return;
+  latency->AddLatencyNumber(ui::INPUT_EVENT_LATENCY_ACK_RWH_COMPONENT, 0, 0);
+  // If this event couldn't have caused a gesture event, and it didn't trigger
+  // rendering, we're done processing it.
+  if (!rendering_scheduled) {
+    latency->AddLatencyNumber(
+        ui::INPUT_EVENT_LATENCY_TERMINATED_NO_SWAP_COMPONENT, 0, 0);
   }
-
-  if (WebInputEvent::isMouseEventType(event.type) && !rendering_scheduled) {
-      latency->AddLatencyNumber(
-          ui::INPUT_EVENT_LATENCY_TERMINATED_MOUSE_COMPONENT, 0, 0);
-    return;
-  }
-
-  if (WebInputEvent::isKeyboardEventType(event.type) && !rendering_scheduled) {
-      latency->AddLatencyNumber(
-          ui::INPUT_EVENT_LATENCY_TERMINATED_KEYBOARD_COMPONENT, 0, 0);
-    return;
-  }
+  ComputeInputLatencyHistograms(event.type, latency_component_id_, *latency,
+                                ack_result);
 }
 
 void RenderWidgetHostLatencyTracker::OnSwapCompositorFrame(
     std::vector<LatencyInfo>* latencies) {
   DCHECK(latencies);
   for (LatencyInfo& latency : *latencies) {
     AddLatencyInfoComponentIds(&latency, latency_component_id_);
     latency.AddLatencyNumber(
         ui::INPUT_EVENT_BROWSER_RECEIVED_RENDERER_SWAP_COMPONENT, 0, 0);
   }
 }
 
 void RenderWidgetHostLatencyTracker::OnFrameSwapped(
     const LatencyInfo& latency,
     bool is_running_navigation_hint_task) {
-
   LatencyInfo::LatencyComponent gpu_swap_end_component;
   if (!latency.FindLatency(
           ui::INPUT_EVENT_LATENCY_TERMINATED_FRAME_SWAP_COMPONENT, 0,
           &gpu_swap_end_component)) {
     return;
   }
 
   LatencyInfo::LatencyComponent gpu_swap_begin_component;
   if (!latency.FindLatency(ui::INPUT_EVENT_GPU_SWAP_BUFFER_COMPONENT, 0,
                            &gpu_swap_begin_component)) {
@@ skipping 13 matching lines @@
   if (!latency.FindLatency(ui::INPUT_EVENT_LATENCY_BEGIN_RWH_COMPONENT,
                            latency_component_id_, nullptr)) {
     return;
   }
 
   ui::SourceEventType source_event_type = latency.source_event_type();
   if (source_event_type == ui::SourceEventType::WHEEL ||
       source_event_type == ui::SourceEventType::TOUCH) {
     ComputeTouchAndWheelScrollLatencyHistograms(
         render_widget_host_delegate_, gpu_swap_begin_component,
-        gpu_swap_end_component, latency_component_id_, latency,
-        source_event_type == ui::SourceEventType::WHEEL ? "Wheel" : "Touch");
+        gpu_swap_end_component, latency_component_id_, latency);
   }
 
   // Compute the old scroll update latency metrics. They are exclusively
   // calculated for touch scrolls, and will be deprecated on M56.
   // (https://crbug.com/649754)
   LatencyInfo::LatencyComponent mouse_wheel_scroll_update_component;
   if (!latency.FindLatency(
           ui::INPUT_EVENT_LATENCY_GENERATE_SCROLL_UPDATE_FROM_MOUSE_WHEEL, 0,
           &mouse_wheel_scroll_update_component)) {
     ComputeScrollLatencyHistograms(
         gpu_swap_begin_component, gpu_swap_end_component, latency_component_id_,
         latency, is_running_navigation_hint_task);
   }
 }
 
 void RenderWidgetHostLatencyTracker::SetDelegate(
     RenderWidgetHostDelegate* delegate) {
   render_widget_host_delegate_ = delegate;
 }
 
 }  // namespace content