| Index: third_party/WebKit/Source/core/frame/FrameView.cpp
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| diff --git a/third_party/WebKit/Source/core/frame/FrameView.cpp b/third_party/WebKit/Source/core/frame/FrameView.cpp
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| index 4e44017bb31be1e9e973df281a7f24a76292cfb6..8e3966173f04510d92f6e7aa796d111483da55b4 100644
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| --- a/third_party/WebKit/Source/core/frame/FrameView.cpp
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| +++ b/third_party/WebKit/Source/core/frame/FrameView.cpp
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| @@ -3959,8 +3959,8 @@ void FrameView::updateViewportIntersectionsForSubtree(LifeCycleUpdateOption phas
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|      updateViewportIntersectionIfNeeded();
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|  
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|      // Notify javascript IntersectionObservers
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| -    if (phases == AllPhases)
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| -        frame().document()->ensureIntersectionObserverController().computeTrackedIntersectionObservations();
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| +    if (phases == AllPhases && frame().document()->intersectionObserverController())
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| +        frame().document()->intersectionObserverController()->computeTrackedIntersectionObservations();
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|  
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|      // Adjust render throttling for iframes based on visibility
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|      bool shouldNotify = !hadValidIntersection || hadEmptyIntersection != m_viewportIntersection.isEmpty();
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| 
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