MouseWheelEventQueue should respect ScrollBegin/End state from RenderWidgetHost.

content/browser/renderer_host/input/input_router_impl.cc

Index: content/browser/renderer_host/input/input_router_impl.cc
diff --git a/content/browser/renderer_host/input/input_router_impl.cc b/content/browser/renderer_host/input/input_router_impl.cc
index 4f00ab21454f89b16da290c120eb65ed6f9dd71e..522e01a493c622d83f6d11d3ed6a8c4e55c03e09 100644
--- a/content/browser/renderer_host/input/input_router_impl.cc
+++ b/content/browser/renderer_host/input/input_router_impl.cc
@@ -311,6 +311,11 @@ void InputRouterImpl::ForwardGestureEventWithLatencyInfo(
   client_->ForwardGestureEventWithLatencyInfo(event, latency_info);
 }
 
+bool InputRouterImpl::IsInGestureScroll() const {
+  return client_->IsInGestureScroll(
+      blink::WebGestureDevice::kWebGestureDeviceTouchpad);
+}
+
 void InputRouterImpl::SendMouseWheelEventImmediately(
     const MouseWheelEventWithLatencyInfo& wheel_event) {
   FilterAndSendWebInputEvent(wheel_event.event, wheel_event.latency);