Add support for new scroll valuators coming from CMT

ui/views/events/event_aura.cc

Index: ui/views/events/event_aura.cc
diff --git a/ui/views/events/event_aura.cc b/ui/views/events/event_aura.cc
index 39ae3f7293a43b085fbf992865739e8aba862781..f6d488d853b5a7c337a0b45b9473f457d38020fe 100644
--- a/ui/views/events/event_aura.cc
+++ b/ui/views/events/event_aura.cc
@@ -59,4 +59,9 @@ MouseWheelEvent::MouseWheelEvent(const NativeEvent& native_event)
       offset_(ui::GetMouseWheelOffset(native_event->native_event())) {
 }
 
+ScrollEvent::ScrollEvent(const NativeEvent& native_event)
+    : MouseEvent(native_event) {
+  ui::GetScrollOffsets(native_event->native_event(), &x_offset_, &y_offset_);
+}
+
 }  // namespace views