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 80d57adebf1fc4a68a57905340aedbbd0da2166a..427c72f1b0cccea4c76735ac4cc135eeaafa083a 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
@@ -688,6 +688,16 @@ 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;