latency: Remove an unused LatencyInfo param.

The |event_count| param is no longer used for anything. So
remove this, and update the usage in the code.

BUG=731202
TBR=tdresser@ as the API owner, for mechanical changes in cc/

Change-Id: Ifd6428fe74086ec621e81d8acec8b21db573cae8
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1691084
Commit-Queue: Sadrul Chowdhury <sadrul@chromium.org>
Reviewed-by: Timothy Dresser <tdresser@chromium.org>
Cr-Commit-Position: refs/heads/master@{#675397}
diff --git a/cc/trees/layer_tree_host_impl.cc b/cc/trees/layer_tree_host_impl.cc
index ed1af2c..9fa738b0 100644
--- a/cc/trees/layer_tree_host_impl.cc
+++ b/cc/trees/layer_tree_host_impl.cc
@@ -2178,15 +2178,15 @@
   ui::LatencyInfo& new_latency_info = metadata.latency_info.back();
   if (CommitToActiveTree()) {
     new_latency_info.AddLatencyNumberWithTimestamp(
-        ui::LATENCY_BEGIN_FRAME_UI_COMPOSITOR_COMPONENT, frame_time, 1);
+        ui::LATENCY_BEGIN_FRAME_UI_COMPOSITOR_COMPONENT, frame_time);
   } else {
     new_latency_info.AddLatencyNumberWithTimestamp(
-        ui::LATENCY_BEGIN_FRAME_RENDERER_COMPOSITOR_COMPONENT, frame_time, 1);
+        ui::LATENCY_BEGIN_FRAME_RENDERER_COMPOSITOR_COMPONENT, frame_time);
 
     base::TimeTicks draw_time = base::TimeTicks::Now();
     for (auto& latency : metadata.latency_info) {
       latency.AddLatencyNumberWithTimestamp(
-          ui::INPUT_EVENT_LATENCY_RENDERER_SWAP_COMPONENT, draw_time, 1);
+          ui::INPUT_EVENT_LATENCY_RENDERER_SWAP_COMPONENT, draw_time);
     }
   }
   ui::LatencyInfo::TraceIntermediateFlowEvents(metadata.latency_info,
diff --git a/cc/trees/proxy_main.cc b/cc/trees/proxy_main.cc
index 7cd0802..b02c96d1 100644
--- a/cc/trees/proxy_main.cc
+++ b/cc/trees/proxy_main.cc
@@ -322,7 +322,7 @@
   ui::LatencyInfo new_latency_info(ui::SourceEventType::FRAME);
   new_latency_info.AddLatencyNumberWithTimestamp(
       ui::LATENCY_BEGIN_FRAME_RENDERER_MAIN_COMPONENT,
-      begin_main_frame_state->begin_frame_args.frame_time, 1);
+      begin_main_frame_state->begin_frame_args.frame_time);
   layer_tree_host_->QueueSwapPromise(
       std::make_unique<LatencyInfoSwapPromise>(new_latency_info));
 
diff --git a/cc/trees/single_thread_proxy.cc b/cc/trees/single_thread_proxy.cc
index 05f5785..0ac0f8b 100644
--- a/cc/trees/single_thread_proxy.cc
+++ b/cc/trees/single_thread_proxy.cc
@@ -830,8 +830,7 @@
   // know we will commit since QueueSwapPromise itself requests a commit.
   ui::LatencyInfo new_latency_info(ui::SourceEventType::FRAME);
   new_latency_info.AddLatencyNumberWithTimestamp(
-      ui::LATENCY_BEGIN_FRAME_UI_MAIN_COMPONENT, begin_frame_args.frame_time,
-      1);
+      ui::LATENCY_BEGIN_FRAME_UI_MAIN_COMPONENT, begin_frame_args.frame_time);
   layer_tree_host_->QueueSwapPromise(
       std::make_unique<LatencyInfoSwapPromise>(new_latency_info));
 
diff --git a/components/viz/service/display/display.cc b/components/viz/service/display/display.cc
index 6162ab2..7710a7f 100644
--- a/components/viz/service/display/display.cc
+++ b/components/viz/service/display/display.cc
@@ -537,7 +537,7 @@
       frame.metadata.latency_info.emplace_back(ui::SourceEventType::FRAME);
       frame.metadata.latency_info.back().AddLatencyNumberWithTimestamp(
           ui::LATENCY_BEGIN_FRAME_DISPLAY_COMPOSITOR_COMPONENT,
-          scheduler_->current_frame_time(), 1);
+          scheduler_->current_frame_time());
     }
 
     std::vector<std::unique_ptr<Surface::PresentationHelper>>
diff --git a/components/viz/service/display/output_surface.cc b/components/viz/service/display/output_surface.cc
index 6e51005e..81f92a2 100644
--- a/components/viz/service/display/output_surface.cc
+++ b/components/viz/service/display/output_surface.cc
@@ -48,11 +48,10 @@
     std::vector<ui::LatencyInfo>* latency_info) {
   for (auto& latency : *latency_info) {
     latency.AddLatencyNumberWithTimestamp(
-        ui::INPUT_EVENT_GPU_SWAP_BUFFER_COMPONENT, response.timings.swap_start,
-        1);
+        ui::INPUT_EVENT_GPU_SWAP_BUFFER_COMPONENT, response.timings.swap_start);
     latency.AddLatencyNumberWithTimestamp(
-        ui::INPUT_EVENT_LATENCY_FRAME_SWAP_COMPONENT, response.timings.swap_end,
-        1);
+        ui::INPUT_EVENT_LATENCY_FRAME_SWAP_COMPONENT,
+        response.timings.swap_end);
   }
 }
 
diff --git a/components/viz/service/display_embedder/skia_output_surface_impl_on_gpu.cc b/components/viz/service/display_embedder/skia_output_surface_impl_on_gpu.cc
index 66cdc3e..fe7fb13 100644
--- a/components/viz/service/display_embedder/skia_output_surface_impl_on_gpu.cc
+++ b/components/viz/service/display_embedder/skia_output_surface_impl_on_gpu.cc
@@ -751,11 +751,10 @@
 
   for (auto& latency : frame.latency_info) {
     latency.AddLatencyNumberWithTimestamp(
-        ui::INPUT_EVENT_GPU_SWAP_BUFFER_COMPONENT, response.timings.swap_start,
-        1);
+        ui::INPUT_EVENT_GPU_SWAP_BUFFER_COMPONENT, response.timings.swap_start);
     latency.AddLatencyNumberWithTimestamp(
-        ui::INPUT_EVENT_LATENCY_FRAME_SWAP_COMPONENT, response.timings.swap_end,
-        1);
+        ui::INPUT_EVENT_LATENCY_FRAME_SWAP_COMPONENT,
+        response.timings.swap_end);
   }
   latency_tracker_.OnGpuSwapBuffersCompleted(frame.latency_info);
 }
diff --git a/components/viz/service/display_embedder/software_output_surface.cc b/components/viz/service/display_embedder/software_output_surface.cc
index e2d4cdb..af0e1858bc 100644
--- a/components/viz/service/display_embedder/software_output_surface.cc
+++ b/components/viz/service/display_embedder/software_output_surface.cc
@@ -62,9 +62,9 @@
   base::TimeTicks swap_time = base::TimeTicks::Now();
   for (auto& latency : frame.latency_info) {
     latency.AddLatencyNumberWithTimestamp(
-        ui::INPUT_EVENT_GPU_SWAP_BUFFER_COMPONENT, swap_time, 1);
+        ui::INPUT_EVENT_GPU_SWAP_BUFFER_COMPONENT, swap_time);
     latency.AddLatencyNumberWithTimestamp(
-        ui::INPUT_EVENT_LATENCY_FRAME_SWAP_COMPONENT, swap_time, 1);
+        ui::INPUT_EVENT_LATENCY_FRAME_SWAP_COMPONENT, swap_time);
   }
 
   DCHECK(stored_latency_info_.empty())
diff --git a/content/browser/compositor/software_browser_compositor_output_surface.cc b/content/browser/compositor/software_browser_compositor_output_surface.cc
index e9d4785..415d703 100644
--- a/content/browser/compositor/software_browser_compositor_output_surface.cc
+++ b/content/browser/compositor/software_browser_compositor_output_surface.cc
@@ -67,9 +67,9 @@
   base::TimeTicks swap_time = base::TimeTicks::Now();
   for (auto& latency : frame.latency_info) {
     latency.AddLatencyNumberWithTimestamp(
-        ui::INPUT_EVENT_GPU_SWAP_BUFFER_COMPONENT, swap_time, 1);
+        ui::INPUT_EVENT_GPU_SWAP_BUFFER_COMPONENT, swap_time);
     latency.AddLatencyNumberWithTimestamp(
-        ui::INPUT_EVENT_LATENCY_FRAME_SWAP_COMPONENT, swap_time, 1);
+        ui::INPUT_EVENT_LATENCY_FRAME_SWAP_COMPONENT, swap_time);
   }
 
   gfx::VSyncProvider* vsync_provider = software_device()->GetVSyncProvider();
diff --git a/content/browser/renderer_host/input/render_widget_host_latency_tracker.cc b/content/browser/renderer_host/input/render_widget_host_latency_tracker.cc
index ec4452bc..1e2ebb1 100644
--- a/content/browser/renderer_host/input/render_widget_host_latency_tracker.cc
+++ b/content/browser/renderer_host/input/render_widget_host_latency_tracker.cc
@@ -143,9 +143,7 @@
       timestamp_original = timestamp_now;
 
     latency->AddLatencyNumberWithTimestamp(
-        ui::INPUT_EVENT_LATENCY_ORIGINAL_COMPONENT,
-        timestamp_original,
-        1);
+        ui::INPUT_EVENT_LATENCY_ORIGINAL_COMPONENT, timestamp_original);
   }
 
   latency->AddLatencyNumberWithTraceName(
@@ -165,10 +163,10 @@
           has_seen_first_gesture_scroll_update_
               ? ui::INPUT_EVENT_LATENCY_SCROLL_UPDATE_ORIGINAL_COMPONENT
               : ui::INPUT_EVENT_LATENCY_FIRST_SCROLL_UPDATE_ORIGINAL_COMPONENT,
-          original_event_timestamp, 1);
+          original_event_timestamp);
       latency->AddLatencyNumberWithTimestamp(
           ui::INPUT_EVENT_LATENCY_SCROLL_UPDATE_LAST_EVENT_COMPONENT,
-          original_event_timestamp, 1);
+          original_event_timestamp);
     }
 
     has_seen_first_gesture_scroll_update_ = true;
diff --git a/content/browser/renderer_host/input/render_widget_host_latency_tracker_unittest.cc b/content/browser/renderer_host/input/render_widget_host_latency_tracker_unittest.cc
index 07a5b71..5f4d05e 100644
--- a/content/browser/renderer_host/input/render_widget_host_latency_tracker_unittest.cc
+++ b/content/browser/renderer_host/input/render_widget_host_latency_tracker_unittest.cc
@@ -37,24 +37,24 @@
     ui::LatencyInfo* latency,
     base::TimeTicks time_stamp) {
   latency->AddLatencyNumberWithTimestamp(ui::INPUT_EVENT_LATENCY_UI_COMPONENT,
-                                         time_stamp, 1);
+                                         time_stamp);
   latency->AddLatencyNumberWithTimestamp(
-      ui::INPUT_EVENT_LATENCY_FRAME_SWAP_COMPONENT, time_stamp, 1);
+      ui::INPUT_EVENT_LATENCY_FRAME_SWAP_COMPONENT, time_stamp);
   latency->AddLatencyNumberWithTimestamp(
-      ui::INPUT_EVENT_GPU_SWAP_BUFFER_COMPONENT, time_stamp, 1);
+      ui::INPUT_EVENT_GPU_SWAP_BUFFER_COMPONENT, time_stamp);
   latency->AddLatencyNumberWithTimestamp(
-      ui::INPUT_EVENT_LATENCY_RENDERER_SWAP_COMPONENT, time_stamp, 1);
+      ui::INPUT_EVENT_LATENCY_RENDERER_SWAP_COMPONENT, time_stamp);
   latency->AddLatencyNumberWithTimestamp(
-      ui::DISPLAY_COMPOSITOR_RECEIVED_FRAME_COMPONENT, time_stamp, 1);
+      ui::DISPLAY_COMPOSITOR_RECEIVED_FRAME_COMPONENT, time_stamp);
 }
 
 void AddFakeComponents(const RenderWidgetHostLatencyTracker& tracker,
                        ui::LatencyInfo* latency) {
   base::TimeTicks now = base::TimeTicks::Now();
   latency->AddLatencyNumberWithTimestamp(
-      ui::INPUT_EVENT_LATENCY_FIRST_SCROLL_UPDATE_ORIGINAL_COMPONENT, now, 1);
+      ui::INPUT_EVENT_LATENCY_FIRST_SCROLL_UPDATE_ORIGINAL_COMPONENT, now);
   latency->AddLatencyNumberWithTimestamp(
-      ui::INPUT_EVENT_LATENCY_SCROLL_UPDATE_LAST_EVENT_COMPONENT, now, 1);
+      ui::INPUT_EVENT_LATENCY_SCROLL_UPDATE_LAST_EVENT_COMPONENT, now);
   AddFakeComponentsWithTimeStamp(tracker, latency, base::TimeTicks::Now());
 }
 
@@ -63,13 +63,10 @@
                                     base::TimeTicks time_stamp) {
   if (main) {
     latency->AddLatencyNumberWithTimestamp(
-        ui::INPUT_EVENT_LATENCY_RENDERING_SCHEDULED_MAIN_COMPONENT, time_stamp,
-        1);
-
+        ui::INPUT_EVENT_LATENCY_RENDERING_SCHEDULED_MAIN_COMPONENT, time_stamp);
   } else {
     latency->AddLatencyNumberWithTimestamp(
-        ui::INPUT_EVENT_LATENCY_RENDERING_SCHEDULED_IMPL_COMPONENT, time_stamp,
-        1);
+        ui::INPUT_EVENT_LATENCY_RENDERING_SCHEDULED_IMPL_COMPONENT, time_stamp);
   }
 }
 
@@ -166,30 +163,30 @@
 
   latency_info.AddLatencyNumberWithTimestamp(
       ui::INPUT_EVENT_LATENCY_FIRST_SCROLL_UPDATE_ORIGINAL_COMPONENT,
-      now + base::TimeDelta::FromMilliseconds(60), 1);
+      now + base::TimeDelta::FromMilliseconds(60));
 
   latency_info.AddLatencyNumberWithTimestamp(
       ui::INPUT_EVENT_LATENCY_RENDERING_SCHEDULED_IMPL_COMPONENT,
-      now + base::TimeDelta::FromMilliseconds(50), 1);
+      now + base::TimeDelta::FromMilliseconds(50));
 
   latency_info.AddLatencyNumberWithTimestamp(
       ui::INPUT_EVENT_LATENCY_RENDERER_SWAP_COMPONENT,
-      now + base::TimeDelta::FromMilliseconds(40), 1);
+      now + base::TimeDelta::FromMilliseconds(40));
 
   latency_info.AddLatencyNumberWithTimestamp(
       ui::DISPLAY_COMPOSITOR_RECEIVED_FRAME_COMPONENT,
-      now + base::TimeDelta::FromMilliseconds(30), 1);
+      now + base::TimeDelta::FromMilliseconds(30));
 
   latency_info.AddLatencyNumberWithTimestamp(
       ui::INPUT_EVENT_LATENCY_BEGIN_RWH_COMPONENT,
-      now + base::TimeDelta::FromMilliseconds(20), 1);
+      now + base::TimeDelta::FromMilliseconds(20));
 
   latency_info.AddLatencyNumberWithTimestamp(
       ui::INPUT_EVENT_GPU_SWAP_BUFFER_COMPONENT,
-      now + base::TimeDelta::FromMilliseconds(10), 1);
+      now + base::TimeDelta::FromMilliseconds(10));
 
   latency_info.AddLatencyNumberWithTimestamp(
-      ui::INPUT_EVENT_LATENCY_FRAME_SWAP_COMPONENT, now, 1);
+      ui::INPUT_EVENT_LATENCY_FRAME_SWAP_COMPONENT, now);
 
   viz_tracker()->OnGpuSwapBuffersCompleted(latency_info);
 
@@ -238,8 +235,7 @@
       wheel.SetTimeStamp(now);
       ui::LatencyInfo wheel_latency(ui::SourceEventType::WHEEL);
       wheel_latency.AddLatencyNumberWithTimestamp(
-          ui::INPUT_EVENT_LATENCY_FIRST_SCROLL_UPDATE_ORIGINAL_COMPONENT, now,
-          1);
+          ui::INPUT_EVENT_LATENCY_FIRST_SCROLL_UPDATE_ORIGINAL_COMPONENT, now);
       AddFakeComponentsWithTimeStamp(*tracker(), &wheel_latency, now);
       AddRenderingScheduledComponent(&wheel_latency, rendering_on_main, now);
       tracker()->OnInputEvent(wheel, &wheel_latency);
@@ -351,7 +347,7 @@
       wheel.SetTimeStamp(now);
       ui::LatencyInfo wheel_latency(ui::SourceEventType::WHEEL);
       wheel_latency.AddLatencyNumberWithTimestamp(
-          ui::INPUT_EVENT_LATENCY_SCROLL_UPDATE_ORIGINAL_COMPONENT, now, 1);
+          ui::INPUT_EVENT_LATENCY_SCROLL_UPDATE_ORIGINAL_COMPONENT, now);
       AddFakeComponentsWithTimeStamp(*tracker(), &wheel_latency, now);
       AddRenderingScheduledComponent(&wheel_latency, rendering_on_main, now);
       tracker()->OnInputEvent(wheel, &wheel_latency);
@@ -543,10 +539,9 @@
       ui::LatencyInfo touch_latency(ui::SourceEventType::TOUCH);
       base::TimeTicks now = base::TimeTicks::Now();
       touch_latency.AddLatencyNumberWithTimestamp(
-          ui::INPUT_EVENT_LATENCY_FIRST_SCROLL_UPDATE_ORIGINAL_COMPONENT, now,
-          1);
+          ui::INPUT_EVENT_LATENCY_FIRST_SCROLL_UPDATE_ORIGINAL_COMPONENT, now);
       touch_latency.AddLatencyNumberWithTimestamp(
-          ui::INPUT_EVENT_LATENCY_SCROLL_UPDATE_LAST_EVENT_COMPONENT, now, 1);
+          ui::INPUT_EVENT_LATENCY_SCROLL_UPDATE_LAST_EVENT_COMPONENT, now);
       AddFakeComponentsWithTimeStamp(*tracker(), &touch_latency, now);
       AddRenderingScheduledComponent(&touch_latency, rendering_on_main, now);
       tracker()->OnInputEvent(touch, &touch_latency);
@@ -660,9 +655,9 @@
       ui::LatencyInfo touch_latency(ui::SourceEventType::TOUCH);
       base::TimeTicks now = base::TimeTicks::Now();
       touch_latency.AddLatencyNumberWithTimestamp(
-          ui::INPUT_EVENT_LATENCY_SCROLL_UPDATE_ORIGINAL_COMPONENT, now, 1);
+          ui::INPUT_EVENT_LATENCY_SCROLL_UPDATE_ORIGINAL_COMPONENT, now);
       touch_latency.AddLatencyNumberWithTimestamp(
-          ui::INPUT_EVENT_LATENCY_SCROLL_UPDATE_LAST_EVENT_COMPONENT, now, 1);
+          ui::INPUT_EVENT_LATENCY_SCROLL_UPDATE_LAST_EVENT_COMPONENT, now);
       AddFakeComponentsWithTimeStamp(*tracker(), &touch_latency, now);
       AddRenderingScheduledComponent(&touch_latency, rendering_on_main, now);
       tracker()->OnInputEvent(touch, &touch_latency);
@@ -761,7 +756,7 @@
       for (bool on_main_thread : on_main) {
         ui::LatencyInfo scrollbar_latency(ui::SourceEventType::SCROLLBAR);
         AddFakeComponentsWithTimeStamp(*tracker(), &scrollbar_latency, now);
-        scrollbar_latency.AddLatencyNumberWithTimestamp(component, now, 1);
+        scrollbar_latency.AddLatencyNumberWithTimestamp(component, now);
         AddRenderingScheduledComponent(&scrollbar_latency, on_main_thread, now);
         tracker()->OnInputEvent(mouse_move, &scrollbar_latency);
         EXPECT_TRUE(scrollbar_latency.FindLatency(
@@ -968,20 +963,17 @@
       fake_latency.AddLatencyNumberWithTimestamp(
           ui::INPUT_EVENT_LATENCY_BEGIN_RWH_COMPONENT,
           base::TimeTicks() +
-              base::TimeDelta::FromMilliseconds(touchstart_timestamps_ms[0]),
-          1);
+              base::TimeDelta::FromMilliseconds(touchstart_timestamps_ms[0]));
 
       fake_latency.AddLatencyNumberWithTimestamp(
           ui::INPUT_EVENT_LATENCY_RENDERER_MAIN_COMPONENT,
           base::TimeTicks() +
-              base::TimeDelta::FromMilliseconds(touchstart_timestamps_ms[1]),
-          1);
+              base::TimeDelta::FromMilliseconds(touchstart_timestamps_ms[1]));
 
       fake_latency.AddLatencyNumberWithTimestamp(
           ui::INPUT_EVENT_LATENCY_ACK_RWH_COMPONENT,
           base::TimeTicks() +
-              base::TimeDelta::FromMilliseconds(touchstart_timestamps_ms[2]),
-          1);
+              base::TimeDelta::FromMilliseconds(touchstart_timestamps_ms[2]));
 
       // Call ComputeInputLatencyHistograms directly to avoid OnInputEventAck
       // overwriting components.
@@ -1012,20 +1004,17 @@
       fake_latency.AddLatencyNumberWithTimestamp(
           ui::INPUT_EVENT_LATENCY_BEGIN_RWH_COMPONENT,
           base::TimeTicks() +
-              base::TimeDelta::FromMilliseconds(touchmove_timestamps_ms[0]),
-          1);
+              base::TimeDelta::FromMilliseconds(touchmove_timestamps_ms[0]));
 
       fake_latency.AddLatencyNumberWithTimestamp(
           ui::INPUT_EVENT_LATENCY_RENDERER_MAIN_COMPONENT,
           base::TimeTicks() +
-              base::TimeDelta::FromMilliseconds(touchmove_timestamps_ms[1]),
-          1);
+              base::TimeDelta::FromMilliseconds(touchmove_timestamps_ms[1]));
 
       fake_latency.AddLatencyNumberWithTimestamp(
           ui::INPUT_EVENT_LATENCY_ACK_RWH_COMPONENT,
           base::TimeTicks() +
-              base::TimeDelta::FromMilliseconds(touchmove_timestamps_ms[2]),
-          1);
+              base::TimeDelta::FromMilliseconds(touchmove_timestamps_ms[2]));
 
       // Call ComputeInputLatencyHistograms directly to avoid OnInputEventAck
       // overwriting components.
@@ -1053,20 +1042,17 @@
       fake_latency.AddLatencyNumberWithTimestamp(
           ui::INPUT_EVENT_LATENCY_BEGIN_RWH_COMPONENT,
           base::TimeTicks() +
-              base::TimeDelta::FromMilliseconds(touchend_timestamps_ms[0]),
-          1);
+              base::TimeDelta::FromMilliseconds(touchend_timestamps_ms[0]));
 
       fake_latency.AddLatencyNumberWithTimestamp(
           ui::INPUT_EVENT_LATENCY_RENDERER_MAIN_COMPONENT,
           base::TimeTicks() +
-              base::TimeDelta::FromMilliseconds(touchend_timestamps_ms[1]),
-          1);
+              base::TimeDelta::FromMilliseconds(touchend_timestamps_ms[1]));
 
       fake_latency.AddLatencyNumberWithTimestamp(
           ui::INPUT_EVENT_LATENCY_ACK_RWH_COMPONENT,
           base::TimeTicks() +
-              base::TimeDelta::FromMilliseconds(touchend_timestamps_ms[2]),
-          1);
+              base::TimeDelta::FromMilliseconds(touchend_timestamps_ms[2]));
 
       // Call ComputeInputLatencyHistograms directly to avoid OnInputEventAck
       // overwriting components.
@@ -1154,20 +1140,17 @@
       fake_latency.AddLatencyNumberWithTimestamp(
           ui::INPUT_EVENT_LATENCY_BEGIN_RWH_COMPONENT,
           base::TimeTicks() +
-              base::TimeDelta::FromMilliseconds(event_timestamps_ms[0]),
-          1);
+              base::TimeDelta::FromMilliseconds(event_timestamps_ms[0]));
 
       fake_latency.AddLatencyNumberWithTimestamp(
           ui::INPUT_EVENT_LATENCY_RENDERER_MAIN_COMPONENT,
           base::TimeTicks() +
-              base::TimeDelta::FromMilliseconds(event_timestamps_ms[1]),
-          1);
+              base::TimeDelta::FromMilliseconds(event_timestamps_ms[1]));
 
       fake_latency.AddLatencyNumberWithTimestamp(
           ui::INPUT_EVENT_LATENCY_ACK_RWH_COMPONENT,
           base::TimeTicks() +
-              base::TimeDelta::FromMilliseconds(event_timestamps_ms[2]),
-          1);
+              base::TimeDelta::FromMilliseconds(event_timestamps_ms[2]));
 
       // Call ComputeInputLatencyHistograms directly to avoid OnInputEventAck
       // overwriting components.
@@ -1206,26 +1189,22 @@
   latency_info.AddLatencyNumberWithTimestamp(
       ui::INPUT_EVENT_LATENCY_ORIGINAL_COMPONENT,
       base::TimeTicks() +
-          base::TimeDelta::FromMicroseconds(event_timestamps_microseconds[0]),
-      1);
+          base::TimeDelta::FromMicroseconds(event_timestamps_microseconds[0]));
 
   latency_info.AddLatencyNumberWithTimestamp(
       ui::INPUT_EVENT_LATENCY_BEGIN_RWH_COMPONENT,
       base::TimeTicks() +
-          base::TimeDelta::FromMicroseconds(event_timestamps_microseconds[0]),
-      1);
+          base::TimeDelta::FromMicroseconds(event_timestamps_microseconds[0]));
 
   latency_info.AddLatencyNumberWithTimestamp(
       ui::INPUT_EVENT_GPU_SWAP_BUFFER_COMPONENT,
       base::TimeTicks() +
-          base::TimeDelta::FromMicroseconds(event_timestamps_microseconds[1]),
-      1);
+          base::TimeDelta::FromMicroseconds(event_timestamps_microseconds[1]));
 
   latency_info.AddLatencyNumberWithTimestamp(
       ui::INPUT_EVENT_LATENCY_FRAME_SWAP_COMPONENT,
       base::TimeTicks() +
-          base::TimeDelta::FromMicroseconds(event_timestamps_microseconds[1]),
-      1);
+          base::TimeDelta::FromMicroseconds(event_timestamps_microseconds[1]));
 
   viz_tracker()->OnGpuSwapBuffersCompleted(latency_info);
 
@@ -1264,20 +1243,17 @@
     fake_latency.AddLatencyNumberWithTimestamp(
         ui::INPUT_EVENT_LATENCY_BEGIN_RWH_COMPONENT,
         base::TimeTicks() +
-            base::TimeDelta::FromMilliseconds(touchstart_timestamps_ms[0]),
-        1);
+            base::TimeDelta::FromMilliseconds(touchstart_timestamps_ms[0]));
 
     fake_latency.AddLatencyNumberWithTimestamp(
         ui::INPUT_EVENT_LATENCY_RENDERER_MAIN_COMPONENT,
         base::TimeTicks() +
-            base::TimeDelta::FromMilliseconds(touchstart_timestamps_ms[1]),
-        1);
+            base::TimeDelta::FromMilliseconds(touchstart_timestamps_ms[1]));
 
     fake_latency.AddLatencyNumberWithTimestamp(
         ui::INPUT_EVENT_LATENCY_ACK_RWH_COMPONENT,
         base::TimeTicks() +
-            base::TimeDelta::FromMilliseconds(touchstart_timestamps_ms[2]),
-        1);
+            base::TimeDelta::FromMilliseconds(touchstart_timestamps_ms[2]));
 
     // Call ComputeInputLatencyHistograms directly to avoid OnInputEventAck
     // overwriting components.
@@ -1298,10 +1274,10 @@
   latency.set_source_event_type(ui::SourceEventType::TOUCHPAD);
   latency.AddLatencyNumberWithTimestamp(
       ui::INPUT_EVENT_LATENCY_ORIGINAL_COMPONENT,
-      base::TimeTicks() + base::TimeDelta::FromMilliseconds(1), 1);
+      base::TimeTicks() + base::TimeDelta::FromMilliseconds(1));
   latency.AddLatencyNumberWithTimestamp(
       ui::INPUT_EVENT_LATENCY_BEGIN_RWH_COMPONENT,
-      base::TimeTicks() + base::TimeDelta::FromMilliseconds(3), 1);
+      base::TimeTicks() + base::TimeDelta::FromMilliseconds(3));
   AddFakeComponentsWithTimeStamp(
       *tracker(), &latency,
       base::TimeTicks() + base::TimeDelta::FromMilliseconds(5));
diff --git a/content/common/input/event_with_latency_info_unittest.cc b/content/common/input/event_with_latency_info_unittest.cc
index 3a1d413..1d5fec2 100644
--- a/content/common/input/event_with_latency_info_unittest.cc
+++ b/content/common/input/event_with_latency_info_unittest.cc
@@ -117,7 +117,7 @@
   MouseEventWithLatencyInfo mouse_0 =
       CreateMouseEvent(WebInputEvent::kMouseMove, 5.0);
   mouse_0.latency.AddLatencyNumberWithTimestamp(
-      ui::INPUT_EVENT_LATENCY_ORIGINAL_COMPONENT, base::TimeTicks(), 1);
+      ui::INPUT_EVENT_LATENCY_ORIGINAL_COMPONENT, base::TimeTicks());
   MouseEventWithLatencyInfo mouse_1 =
       CreateMouseEvent(WebInputEvent::kMouseMove, 10.0);
 
diff --git a/content/renderer/input/render_widget_input_handler.cc b/content/renderer/input/render_widget_input_handler.cc
index 2281020..e23bdc9 100644
--- a/content/renderer/input/render_widget_input_handler.cc
+++ b/content/renderer/input/render_widget_input_handler.cc
@@ -619,7 +619,7 @@
             last_injected_gesture_was_begin_
                 ? ui::INPUT_EVENT_LATENCY_FIRST_SCROLL_UPDATE_ORIGINAL_COMPONENT
                 : ui::INPUT_EVENT_LATENCY_SCROLL_UPDATE_ORIGINAL_COMPONENT,
-            original_timestamp, 1);
+            original_timestamp);
       } else {
         // If we're injecting a GSU in response to a GSU (touch drags of the
         // scrollbar thumb in Blink handles GSUs, and reverses them with
diff --git a/ui/events/blink/input_handler_proxy.cc b/ui/events/blink/input_handler_proxy.cc
index 19480fd6..74cf707c9 100644
--- a/ui/events/blink/input_handler_proxy.cc
+++ b/ui/events/blink/input_handler_proxy.cc
@@ -390,7 +390,7 @@
       (is_first_gesture_scroll_update_)
           ? ui::INPUT_EVENT_LATENCY_FIRST_SCROLL_UPDATE_ORIGINAL_COMPONENT
           : ui::INPUT_EVENT_LATENCY_SCROLL_UPDATE_ORIGINAL_COMPONENT,
-      original_timestamp, 1);
+      original_timestamp);
 }
 
 void InputHandlerProxy::DispatchQueuedInputEvents() {
@@ -406,7 +406,7 @@
     // output latency.
     LatencyInfo* latency_info = event_with_callback->mutable_latency_info();
     latency_info->AddLatencyNumberWithTimestamp(
-        ui::INPUT_EVENT_LATENCY_SCROLL_UPDATE_RAF_TIME_COMPONENT, now, 1);
+        ui::INPUT_EVENT_LATENCY_SCROLL_UPDATE_RAF_TIME_COMPONENT, now);
 
     DispatchSingleInputEvent(std::move(event_with_callback), now);
   }
diff --git a/ui/events/event.cc b/ui/events/event.cc
index 2874bd5..15252f61 100644
--- a/ui/events/event.cc
+++ b/ui/events/event.cc
@@ -521,7 +521,7 @@
       pointer_details_(GetMousePointerDetailsFromNative(native_event)) {
   latency()->set_source_event_type(ui::SourceEventType::MOUSE);
   latency()->AddLatencyNumberWithTimestamp(
-      INPUT_EVENT_LATENCY_ORIGINAL_COMPONENT, time_stamp(), 1);
+      INPUT_EVENT_LATENCY_ORIGINAL_COMPONENT, time_stamp());
   latency()->AddLatencyNumber(INPUT_EVENT_LATENCY_UI_COMPONENT);
   if (type() == ET_MOUSE_PRESSED || type() == ET_MOUSE_RELEASED)
     SetClickCount(GetRepeatCount(*this));
@@ -759,7 +759,7 @@
       hovering_(false),
       pointer_details_(GetTouchPointerDetailsFromNative(native_event)) {
   latency()->AddLatencyNumberWithTimestamp(
-      INPUT_EVENT_LATENCY_ORIGINAL_COMPONENT, time_stamp(), 1);
+      INPUT_EVENT_LATENCY_ORIGINAL_COMPONENT, time_stamp());
   latency()->AddLatencyNumber(INPUT_EVENT_LATENCY_UI_COMPONENT);
 
   if (type() == ET_TOUCH_RELEASED || type() == ET_TOUCH_CANCELLED)
@@ -934,7 +934,7 @@
       code_(CodeFromNative(native_event)),
       is_char_(IsCharFromNative(native_event)) {
   latency()->AddLatencyNumberWithTimestamp(
-      INPUT_EVENT_LATENCY_ORIGINAL_COMPONENT, time_stamp(), 1);
+      INPUT_EVENT_LATENCY_ORIGINAL_COMPONENT, time_stamp());
   latency()->AddLatencyNumber(INPUT_EVENT_LATENCY_UI_COMPONENT);
 
   if (IsRepeated(*this))
diff --git a/ui/latency/average_lag_tracker_unittest.cc b/ui/latency/average_lag_tracker_unittest.cc
index 82d7e89..dc4d7c7 100644
--- a/ui/latency/average_lag_tracker_unittest.cc
+++ b/ui/latency/average_lag_tracker_unittest.cc
@@ -39,10 +39,9 @@
 
     touch_latency.AddLatencyNumberWithTimestamp(
         ui::INPUT_EVENT_LATENCY_FIRST_SCROLL_UPDATE_ORIGINAL_COMPONENT,
-        event_time, 1);
+        event_time);
     touch_latency.AddLatencyNumberWithTimestamp(
-        ui::INPUT_EVENT_LATENCY_SCROLL_UPDATE_LAST_EVENT_COMPONENT, event_time,
-        1);
+        ui::INPUT_EVENT_LATENCY_SCROLL_UPDATE_LAST_EVENT_COMPONENT, event_time);
     average_lag_tracker_->AddLatencyInFrame(touch_latency, frame_time,
                                             "ScrollBegin");
   }
@@ -56,11 +55,9 @@
     touch_latency.set_predicted_scroll_update_delta(
         predicted_delta != 0 ? predicted_delta : delta);
     touch_latency.AddLatencyNumberWithTimestamp(
-        ui::INPUT_EVENT_LATENCY_SCROLL_UPDATE_ORIGINAL_COMPONENT, event_time,
-        1);
+        ui::INPUT_EVENT_LATENCY_SCROLL_UPDATE_ORIGINAL_COMPONENT, event_time);
     touch_latency.AddLatencyNumberWithTimestamp(
-        ui::INPUT_EVENT_LATENCY_SCROLL_UPDATE_LAST_EVENT_COMPONENT, event_time,
-        1);
+        ui::INPUT_EVENT_LATENCY_SCROLL_UPDATE_LAST_EVENT_COMPONENT, event_time);
     average_lag_tracker_->AddLatencyInFrame(touch_latency, frame_time,
                                             "ScrollUpdate");
   }
diff --git a/ui/latency/latency_info.cc b/ui/latency/latency_info.cc
index 5a1a4d9c..c1ef1d7 100644
--- a/ui/latency/latency_info.cc
+++ b/ui/latency/latency_info.cc
@@ -184,7 +184,7 @@
 
   for (const auto& lc : other.latency_components()) {
     if (lc.first == type) {
-      AddLatencyNumberWithTimestamp(lc.first, lc.second, 1);
+      AddLatencyNumberWithTimestamp(lc.first, lc.second);
     }
   }
 
@@ -208,7 +208,7 @@
 
   for (const auto& lc : other.latency_components()) {
     if (!FindLatency(lc.first, nullptr)) {
-      AddLatencyNumberWithTimestamp(lc.first, lc.second, 1);
+      AddLatencyNumberWithTimestamp(lc.first, lc.second);
     }
   }
 
@@ -221,28 +221,24 @@
 }
 
 void LatencyInfo::AddLatencyNumber(LatencyComponentType component) {
-  AddLatencyNumberWithTimestampImpl(component, base::TimeTicks::Now(), 1,
-                                    nullptr);
+  AddLatencyNumberWithTimestampImpl(component, base::TimeTicks::Now(), nullptr);
 }
 
 void LatencyInfo::AddLatencyNumberWithTraceName(
     LatencyComponentType component,
     const char* trace_name_str) {
-  AddLatencyNumberWithTimestampImpl(component, base::TimeTicks::Now(), 1,
+  AddLatencyNumberWithTimestampImpl(component, base::TimeTicks::Now(),
                                     trace_name_str);
 }
 
-void LatencyInfo::AddLatencyNumberWithTimestamp(
-    LatencyComponentType component,
-    base::TimeTicks time,
-    uint32_t event_count) {
-  AddLatencyNumberWithTimestampImpl(component, time, event_count, nullptr);
+void LatencyInfo::AddLatencyNumberWithTimestamp(LatencyComponentType component,
+                                                base::TimeTicks time) {
+  AddLatencyNumberWithTimestampImpl(component, time, nullptr);
 }
 
 void LatencyInfo::AddLatencyNumberWithTimestampImpl(
     LatencyComponentType component,
     base::TimeTicks time,
-    uint32_t event_count,
     const char* trace_name_str) {
   const unsigned char* latency_info_enabled =
       g_latency_info_enabled.Get().latency_info_enabled;
diff --git a/ui/latency/latency_info.h b/ui/latency/latency_info.h
index 47140fc..333f0590837 100644
--- a/ui/latency/latency_info.h
+++ b/ui/latency/latency_info.h
@@ -162,8 +162,7 @@
   // Modifies the current sequence number and adds a certain number of events
   // for a specific component.
   void AddLatencyNumberWithTimestamp(LatencyComponentType component,
-                                     base::TimeTicks time,
-                                     uint32_t event_count);
+                                     base::TimeTicks time);
 
   // Returns true if a component with |type| is found in the latency component.
   // The first such component (when iterating over latency_components_) is
@@ -210,7 +209,6 @@
  private:
   void AddLatencyNumberWithTimestampImpl(LatencyComponentType component,
                                          base::TimeTicks time,
-                                         uint32_t event_count,
                                          const char* trace_name_str);
 
   // Converts latencyinfo into format that can be dumped into trace buffer.
diff --git a/ui/latency/latency_info_unittest.cc b/ui/latency/latency_info_unittest.cc
index e2269ae..833f6c3 100644
--- a/ui/latency/latency_info_unittest.cc
+++ b/ui/latency/latency_info_unittest.cc
@@ -24,10 +24,10 @@
   info.set_trace_id(1);
   EXPECT_FALSE(info.began());
   info.AddLatencyNumberWithTimestamp(INPUT_EVENT_LATENCY_BEGIN_RWH_COMPONENT,
-                                     ToTestTimeTicks(100), 1);
+                                     ToTestTimeTicks(100));
   EXPECT_TRUE(info.began());
   info.AddLatencyNumberWithTimestamp(INPUT_EVENT_LATENCY_ORIGINAL_COMPONENT,
-                                     ToTestTimeTicks(1000), 2);
+                                     ToTestTimeTicks(1000));
 
   EXPECT_EQ(info.latency_components().size(), 2u);
   base::TimeTicks timestamp;
@@ -45,13 +45,13 @@
   info1.set_trace_id(1);
   info1.AddLatencyNumberWithTimestamp(
       INPUT_EVENT_LATENCY_SCROLL_UPDATE_LAST_EVENT_COMPONENT,
-      ToTestTimeTicks(1234), 1);
+      ToTestTimeTicks(1234));
   info1.set_scroll_update_delta(-3);
 
   info2.set_trace_id(2);
   info2.AddLatencyNumberWithTimestamp(
       INPUT_EVENT_LATENCY_SCROLL_UPDATE_LAST_EVENT_COMPONENT,
-      ToTestTimeTicks(2345), 1);
+      ToTestTimeTicks(2345));
   info2.set_scroll_update_delta(5);
 
   info1.CoalesceScrollUpdateWith(info2);
diff --git a/ui/views/win/hwnd_message_handler.cc b/ui/views/win/hwnd_message_handler.cc
index da11a3de..953d71f 100644
--- a/ui/views/win/hwnd_message_handler.cc
+++ b/ui/views/win/hwnd_message_handler.cc
@@ -3037,7 +3037,7 @@
       ui::GetModifiersFromKeyState());
 
   event.latency()->AddLatencyNumberWithTimestamp(
-      ui::INPUT_EVENT_LATENCY_ORIGINAL_COMPONENT, event_time, 1);
+      ui::INPUT_EVENT_LATENCY_ORIGINAL_COMPONENT, event_time);
 
   // Release the pointer id for touch release events.
   if (event_type == ui::ET_TOUCH_RELEASED)
@@ -3193,7 +3193,7 @@
   event.set_flags(ui::GetModifiersFromKeyState());
 
   event.latency()->AddLatencyNumberWithTimestamp(
-      ui::INPUT_EVENT_LATENCY_ORIGINAL_COMPONENT, time_stamp, 1);
+      ui::INPUT_EVENT_LATENCY_ORIGINAL_COMPONENT, time_stamp);
 
   touch_events->push_back(event);
 }
diff --git a/ui/views/win/pen_event_processor.cc b/ui/views/win/pen_event_processor.cc
index 6e8f488..36de1de 100644
--- a/ui/views/win/pen_event_processor.cc
+++ b/ui/views/win/pen_event_processor.cc
@@ -199,7 +199,7 @@
       flags | ui::GetModifiersFromKeyState());
   event->set_hovering(event_type == ui::ET_TOUCH_RELEASED);
   event->latency()->AddLatencyNumberWithTimestamp(
-      ui::INPUT_EVENT_LATENCY_ORIGINAL_COMPONENT, event_time, 1);
+      ui::INPUT_EVENT_LATENCY_ORIGINAL_COMPONENT, event_time);
   return event;
 }