Add TimeToScrollUpdateSwapBegin2 to UKM

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 53 matching lines @@
 
   // Returns the ID that uniquely describes this component to the latency
   // subsystem.
   int64_t latency_component_id() const { return latency_component_id_; }
 
   // A delegate is used to get the url to be stored in Rappor Sample.
   // If delegate is null no Rappor sample will be reported.
   void SetDelegate(RenderWidgetHostDelegate*);
 
  private:
+  int32_t GetUkmSourceId();
+
   // ui::LatencyTracker:
   void ReportRapporScrollLatency(
       const std::string& name,
       const ui::LatencyInfo::LatencyComponent& start_component,
       const ui::LatencyInfo::LatencyComponent& end_component) override;
 
+  // ui::LatencyTracker:
+  void ReportUkmScrollLatency(
+      const std::string& name,
+      const ui::LatencyInfo::LatencyComponent& start_component,
+      const ui::LatencyInfo::LatencyComponent& end_component) override;
+
   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_