UMA metrics for use count of wheel and touch scrolls.

cc/test/stub_layer_tree_host_client.h

Index: cc/test/stub_layer_tree_host_client.h
diff --git a/cc/test/stub_layer_tree_host_client.h b/cc/test/stub_layer_tree_host_client.h
index 2c6b60796f928cbb5fd067688700145e51a7d63b..dca0005700810e3e127eef5ed054bdf518e2a1d6 100644
--- a/cc/test/stub_layer_tree_host_client.h
+++ b/cc/test/stub_layer_tree_host_client.h
@@ -24,6 +24,8 @@ class StubLayerTreeHostClient : public LayerTreeHostClient {
                            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 {}