| Index: Source/core/frame/RootFrameViewport.cpp | 
| diff --git a/Source/core/frame/RootFrameViewport.cpp b/Source/core/frame/RootFrameViewport.cpp | 
| index fd02ee864497c404f91b0c4a4392a3a52ef5727b..f241c2c710a7c143945db81e1e754dfb2e951087 100644 | 
| --- a/Source/core/frame/RootFrameViewport.cpp | 
| +++ b/Source/core/frame/RootFrameViewport.cpp | 
| @@ -328,5 +328,11 @@ void RootFrameViewport::updateCompositorScrollAnimations() | 
| layoutViewport().updateCompositorScrollAnimations(); | 
| } | 
|  | 
| +DEFINE_TRACE(RootFrameViewport) | 
| +{ | 
| +    visitor->trace(m_visualViewport); | 
| +    visitor->trace(m_layoutViewport); | 
| +    ScrollableArea::trace(visitor); | 
| +} | 
|  | 
| } // namespace blink | 
|  |