[DNS] Don't adjust the scroll position if the anchor element changes in size

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

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef ScrollAnchor_h
 #define ScrollAnchor_h
 
 #include "core/CoreExport.h"
 #include "platform/geometry/LayoutPoint.h"
 #include "platform/heap/Handle.h"
@@ skipping 67 matching lines @@
 
     // The scroller that owns and is adjusted by this ScrollAnchor.
     Member<ScrollableArea> m_scroller;
 
     // The LayoutObject we should anchor to. Lazily computed.
     LayoutObject* m_anchorObject;
 
     // Which corner of m_anchorObject's bounding box to anchor to.
     Corner m_corner;
 
-    // Location of m_layoutObject relative to scroller at time of save().
+    // Location of m_anchorObject relative to scroller at time of save().
     LayoutPoint m_savedRelativeOffset;
+
+    // The size of the m_anchorObject at the time of save().
+    LayoutSize m_savedAnchorSize;
 };
 
 } // namespace blink
 
 #endif // ScrollAnchor_h