Add DVR API for scroll event injection.

Bug: 62226675
Test: manual, vrcore build
Change-Id: Ic7d329eba8003b0e294b3a11a83ed5f868b801f8
diff --git a/services/vr/virtual_touchpad/VirtualTouchpadEvdev.h b/services/vr/virtual_touchpad/VirtualTouchpadEvdev.h
index 2fb8ff3..c9578bf 100644
--- a/services/vr/virtual_touchpad/VirtualTouchpadEvdev.h
+++ b/services/vr/virtual_touchpad/VirtualTouchpadEvdev.h
@@ -21,6 +21,7 @@
   status_t Detach() override;
   status_t Touch(int touchpad, float x, float y, float pressure) override;
   status_t ButtonState(int touchpad, int buttons) override;
+  status_t Scroll(int touchpad, float x, float y) override;
   void dumpInternal(String8& result) override;
 
  protected: