Plumb smooth scrolling in Chromium compositor

content/browser/renderer_host/input/touch_action_filter.cc

Index: content/browser/renderer_host/input/touch_action_filter.cc
diff --git a/content/browser/renderer_host/input/touch_action_filter.cc b/content/browser/renderer_host/input/touch_action_filter.cc
index b12f283c3e107fa018cbb7d06d0007c3a128b011..aff592ffa8a3d57b3b397ebbb0ac04d07f473a1e 100644
--- a/content/browser/renderer_host/input/touch_action_filter.cc
+++ b/content/browser/renderer_host/input/touch_action_filter.cc
@@ -64,7 +64,8 @@ bool TouchActionFilter::FilterGestureEvent(WebGestureEvent* gesture_event) {
       if (gesture_event->sourceDevice != blink::WebGestureDeviceTouchscreen)
         break;
       // Touchscreen flings should always have non-zero velocity.
-      DCHECK(gesture_event->data.flingStart.velocityX ||
+      DCHECK(gesture_event->data.flingStart.isSmoothScroll ||
+             gesture_event->data.flingStart.velocityX ||
              gesture_event->data.flingStart.velocityY);
       if (!drop_scroll_gesture_events_) {
         // Flings restricted to a specific axis shouldn't permit velocity