Remove LatencyInfo::sequence_number. (May break metrics).

content/browser/renderer_host/input/render_widget_host_latency_tracker.h

 // 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.
 
 #ifndef CONTENT_BROWSER_RENDERER_HOST_INPUT_RENDER_WIDGET_HOST_LATENCY_TRACKER_H_
 #define CONTENT_BROWSER_RENDERER_HOST_INPUT_RENDER_WIDGET_HOST_LATENCY_TRACKER_H_
 
 #include <stdint.h>
 
 #include <vector>
@@ skipping 70 matching lines @@
       const ui::LatencyInfo::LatencyComponent& end_component) override;
 
   // ui::LatencyTracker:
   void ReportUkmScrollLatency(
       const std::string& event_name,
       const std::string& metric_name,
       const ui::LatencyInfo::LatencyComponent& start_component,
       const ui::LatencyInfo::LatencyComponent& end_component) override;
 
   ukm::SourceId ukm_source_id_;
-  int64_t last_event_id_;
+
   int64_t latency_component_id_;
   float device_scale_factor_;
   bool has_seen_first_gesture_scroll_update_;
   // Whether the current stream of touch events includes more than one active
   // touch point. This is set in OnInputEvent, and cleared in OnInputEventAck.
   bool active_multi_finger_gesture_;
   // Whether the touch start for the current stream of touch events had its
   // default action prevented. Only valid for single finger gestures.
   bool touch_start_default_prevented_;
 
   RenderWidgetHostDelegate* render_widget_host_delegate_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderWidgetHostLatencyTracker);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_INPUT_RENDER_WIDGET_HOST_LATENCY_TRACKER_H_