@Override
    public void onScroll(int source, Node node, float x, float y) {
        VRTComponent component = weakComponent.get();
        if (component == null){
            return;
        }

        WritableMap event = Arguments.createMap();
        event.putInt("source", source);
        WritableArray scrollPos = Arguments.createArray();
        scrollPos.pushDouble(x);
        scrollPos.pushDouble(y);

        event.putArray("scrollPos", scrollPos);
        component.getReactContext().getJSModule(RCTEventEmitter.class).receiveEvent(
                component.getId(),
                ViroEvents.ON_SCROLL,
                event);
    }
Represents all java-to-javascript calls that can be triggered from an EventDelegate.
android/viro_bridge/src/main/java/com/viromedia/bridge/utility/ComponentEventDelegate.java