Disable scroll anchoring is an element within the scroll changes its in-flow state

third_party/WebKit/Source/core/layout/LayoutObject.h

Index: third_party/WebKit/Source/core/layout/LayoutObject.h
diff --git a/third_party/WebKit/Source/core/layout/LayoutObject.h b/third_party/WebKit/Source/core/layout/LayoutObject.h
index a2816297526db24266be19aff26e2af74e2d2f99..9364c8538fe03f3c404e8e2237501027d676398e 100644
--- a/third_party/WebKit/Source/core/layout/LayoutObject.h
+++ b/third_party/WebKit/Source/core/layout/LayoutObject.h
@@ -1588,6 +1588,10 @@ private:
 
     void setNeedsOverflowRecalcAfterStyleChange();
 
+    // Walk up the parent chain and find the first scrolling block to disable
+    // scroll anchoring on.
+    void setScrollAnchorDisablingStyleChangedOnAncestor();
+
     // FIXME: This should be 'markContaingBoxChainForOverflowRecalc when we make LayoutBox
     // recomputeOverflow-capable. crbug.com/437012 and crbug.com/434700.
     inline void markAncestorsForOverflowRecalcIfNeeded();