Add a sampling scheme to ScrollUpdate.Touch UKM

content/browser/renderer_host/render_widget_host_impl.cc

 // Copyright (c) 2012 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/render_widget_host_impl.h"
 
 #include <math.h>
 
 #include <set>
 #include <tuple>
@@ skipping 272 matching lines @@
       ignore_input_events_(false),
       text_direction_updated_(false),
       text_direction_(blink::kWebTextDirectionLeftToRight),
       text_direction_canceled_(false),
       suppress_events_until_keydown_(false),
       pending_mouse_lock_request_(false),
       allow_privileged_mouse_lock_(false),
       is_last_unlocked_by_target_(false),
       has_touch_handler_(false),
       is_in_touchpad_gesture_fling_(false),
-      latency_tracker_(),
+      latency_tracker_(true),
       next_browser_snapshot_id_(1),
       owned_by_render_frame_host_(false),
       is_focused_(false),
       hung_renderer_delay_(
           base::TimeDelta::FromMilliseconds(kHungRendererDelayMs)),
       hang_monitor_event_type_(blink::WebInputEvent::kUndefined),
       last_event_type_(blink::WebInputEvent::kUndefined),
       new_content_rendering_delay_(
           base::TimeDelta::FromMilliseconds(kNewContentRenderingDelayMs)),
       current_content_source_id_(0),
@@ skipping 2392 matching lines @@
           device::mojom::WakeLockType::PreventDisplaySleep,
           device::mojom::WakeLockReason::ReasonOther, "GetSnapshot",
           std::move(request));
     }
   }
   return wake_lock_.get();
 }
 #endif
 
 }  // namespace content