Add support for new scroll valuators coming from CMT

ui/views/widget/native_widget_aura.cc

Index: ui/views/widget/native_widget_aura.cc
diff --git a/ui/views/widget/native_widget_aura.cc b/ui/views/widget/native_widget_aura.cc
index 931eca58a7996542bf207adca9baddc4161af030..bf2ca139e43cdc03d65e55e2cb27f5a3595f4885 100644
--- a/ui/views/widget/native_widget_aura.cc
+++ b/ui/views/widget/native_widget_aura.cc
@@ -654,6 +654,10 @@ bool NativeWidgetAura::OnMouseEvent(aura::MouseEvent* event) {
     MouseWheelEvent wheel_event(event);
     return delegate_->OnMouseEvent(wheel_event);
   }
+  if (event->type() == ui::ET_SCROLL) {
+    ScrollEvent scroll_event(static_cast<aura::ScrollEvent*>(event));
+    return delegate_->OnMouseEvent(scroll_event);
+  }
   MouseEvent mouse_event(event);
   if (tooltip_manager_.get())
     tooltip_manager_->UpdateTooltip();