scheduler: Handle mouse wheel event disposition correctly

third_party/WebKit/Source/platform/scheduler/renderer/renderer_scheduler_impl.cc

Index: third_party/WebKit/Source/platform/scheduler/renderer/renderer_scheduler_impl.cc
diff --git a/third_party/WebKit/Source/platform/scheduler/renderer/renderer_scheduler_impl.cc b/third_party/WebKit/Source/platform/scheduler/renderer/renderer_scheduler_impl.cc
index 0d5d624c3473fbf9c57ddb54950c5c75b4a7da83..45c9f91bc50705923875a493dc69a2258abb2acf 100644
--- a/third_party/WebKit/Source/platform/scheduler/renderer/renderer_scheduler_impl.cc
+++ b/third_party/WebKit/Source/platform/scheduler/renderer/renderer_scheduler_impl.cc
@@ -644,6 +644,16 @@ void RendererSchedulerImpl::UpdateForInputEventOnCompositorThread(
       AnyThread().awaiting_touch_start_response = false;
       break;
 
+    case blink::WebInputEvent::MouseWheel:
+      AnyThread().last_gesture_was_compositor_driven =
+          input_event_state == InputEventState::EVENT_CONSUMED_BY_COMPOSITOR;
+      AnyThread().awaiting_touch_start_response = false;
+      // If the event was sent to the main thread, assume the default gesture is
+      // prevented until we see evidence otherwise.
+      AnyThread().default_gesture_prevented =
+          !AnyThread().last_gesture_was_compositor_driven;
+      break;
+
     case blink::WebInputEvent::Undefined:
       break;