UMA metrics for use count of wheel and touch scrolls.

ui/compositor/compositor.h

Index: ui/compositor/compositor.h
diff --git a/ui/compositor/compositor.h b/ui/compositor/compositor.h
index f94748b7ff87b257fe7d514caabd7042cde494c1..9155b3eea30360618e88a27c39a5ad31e09c407a 100644
--- a/ui/compositor/compositor.h
+++ b/ui/compositor/compositor.h
@@ -359,6 +359,8 @@ class COMPOSITOR_EXPORT Compositor
                            const gfx::Vector2dF& elastic_overscroll_delta,
                            float page_scale,
                            float top_controls_delta) override {}
+  void RecordWheelAndTouchScrollingCount(bool has_scrolled_by_wheel,
+                                         bool has_scrolled_by_touch) override {}
   void RequestNewCompositorFrameSink() override;
   void DidInitializeCompositorFrameSink() override {}
   void DidFailToInitializeCompositorFrameSink() override;