GSB uses delta_hints to calculate scrolling chain.

third_party/WebKit/Source/core/page/scrolling/ScrollState.cpp

Index: third_party/WebKit/Source/core/page/scrolling/ScrollState.cpp
diff --git a/third_party/WebKit/Source/core/page/scrolling/ScrollState.cpp b/third_party/WebKit/Source/core/page/scrolling/ScrollState.cpp
index fe5daa5c507dfb1514c22a6fe3ce551f2426da68..16e90b2ff7915f61bf605b0127dcc121835102a9 100644
--- a/third_party/WebKit/Source/core/page/scrolling/ScrollState.cpp
+++ b/third_party/WebKit/Source/core/page/scrolling/ScrollState.cpp
@@ -32,6 +32,9 @@ ScrollState* ScrollState::Create(ScrollStateInit init) {
       WTF::MakeUnique<ScrollStateData>();
   scroll_state_data->delta_x = init.deltaX();
   scroll_state_data->delta_y = init.deltaY();
+  scroll_state_data->delta_x_hint = init.deltaXHint();
+  scroll_state_data->delta_y_hint = init.deltaYHint();
+  scroll_state_data->ignore_delta_hints = init.ignoreDeltaHints();
   scroll_state_data->position_x = init.positionX();
   scroll_state_data->position_y = init.positionY();
   scroll_state_data->velocity_x = init.velocityX();