Clear scroll anchor on all parent scrollers from ScrollAnchor::clear

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

Index: third_party/WebKit/Source/core/layout/ScrollAnchor.h
diff --git a/third_party/WebKit/Source/core/layout/ScrollAnchor.h b/third_party/WebKit/Source/core/layout/ScrollAnchor.h
index 865cabe05762f36a21d409c172928e19d73bc023..eff281568cd7fd2842e6624438be1e98bc1a6063 100644
--- a/third_party/WebKit/Source/core/layout/ScrollAnchor.h
+++ b/third_party/WebKit/Source/core/layout/ScrollAnchor.h
@@ -34,10 +34,14 @@ class CORE_EXPORT ScrollAnchor final {
   // save() and cached until the next call to clear().
   LayoutObject* anchorObject() const { return m_anchorObject; }
 
-  // Indicates that the next save() should compute a new anchor. (In certain
-  // cases the previous anchor will be reused; see comments in restore.)
+  // Indicates that the next save() should compute a new anchor for the
+  // containing scroller and all ancestor scrollers (In certain cases the

[skobes, 2016/10/10 21:34:35]

You can delete the sentence in parentheses, it's a vestige of bounce
suppression.

+  // previous anchor will be reused; see comments in restore.)
   void clear();
 
+  // Sets the anchor object to null.
+  void releaseAnchor();
+
   // Records the anchor's location in relation to the scroller. Should be
   // called when the scroller is about to be laid out.
   void save();
@@ -58,12 +62,13 @@ class CORE_EXPORT ScrollAnchor final {
   // Checks if we hold any references to the specified object.
   bool refersTo(const LayoutObject*) const;
 
-  // Notifies us that an object will be removed from the layout tree.
-  void notifyRemoved(LayoutObject*);
-
   DEFINE_INLINE_TRACE() { visitor->trace(m_scroller); }
 
  private:
+  // Indicates that the next save() should compute a new anchor just for the
+  // containing scroller.
+  void clearForContainingScroller();
+
   void findAnchor();
   bool computeScrollAnchorDisablingStyleChanged();