Bubble scroll events from WebView guest to embedder.

content/browser/frame_host/render_widget_host_view_guest.cc

Index: content/browser/frame_host/render_widget_host_view_guest.cc
diff --git a/content/browser/frame_host/render_widget_host_view_guest.cc b/content/browser/frame_host/render_widget_host_view_guest.cc
index f5a04c4cc6fb1e2c152e847173fabf94ac7f013d..8e6352ef1dc5af5823102beb56a2ae192fa94fdf 100644
--- a/content/browser/frame_host/render_widget_host_view_guest.cc
+++ b/content/browser/frame_host/render_widget_host_view_guest.cc
@@ -663,4 +663,29 @@ void RenderWidgetHostViewGuest::OnHandleInputEvent(
   }
 }
 
+namespace {
+
+bool IsScrollEvent(const blink::WebInputEvent& event) {
+  return event.type == blink::WebInputEvent::GestureScrollBegin ||
+         event.type == blink::WebInputEvent::GestureScrollUpdate ||
+         event.type == blink::WebInputEvent::GestureScrollEnd ||
+         event.type == blink::WebInputEvent::MouseWheel;
+}
+
+}  // namespace
+
+void RenderWidgetHostViewGuest::GestureEventAck(
+    const blink::WebGestureEvent& event,
+    InputEventAckState ack_result) {
+  if (IsScrollEvent(event))
+    guest_->SendScrollCompletion(ack_result == INPUT_EVENT_ACK_STATE_CONSUMED);
+}
+
+void RenderWidgetHostViewGuest::WheelEventAck(
+    const blink::WebMouseWheelEvent& event,
+    InputEventAckState ack_result) {
+  if (IsScrollEvent(event))
+    guest_->SendScrollCompletion(ack_result == INPUT_EVENT_ACK_STATE_CONSUMED);
+}
+
 }  // namespace content