Clamping shouldn't clear the fragment anchor.

third_party/WebKit/Source/core/paint/PaintLayerScrollableArea.cpp

 /*
  * Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011, 2012 Apple Inc. All rights
  * reserved.
  *
  * Portions are Copyright (C) 1998 Netscape Communications Corporation.
  *
  * Other contributors:
  *   Robert O'Callahan <roc+@cs.cmu.edu>
  *   David Baron <dbaron@fas.harvard.edu>
  *   Christian Biesinger <cbiesinger@gmail.com>
@@ skipping 436 matching lines @@
     cache->handleScrollPositionChanged(&box());
   box().view()->clearHitTestCache();
 
   // Inform the FrameLoader of the new scroll position, so it can be restored
   // when navigating back.
   if (layer()->isRootLayer()) {
     frameView->frame().loader().saveScrollState();
     frameView->didChangeScrollOffset();
   }
 
-  // All scrolls clear the fragment anchor.
-  frameView->clearFragmentAnchor();
+  if (scrollTypeClearsFragmentAnchor(scrollType))
+    frameView->clearFragmentAnchor();
 
   // Clear the scroll anchor, unless it is the reason for this scroll.
   if (RuntimeEnabledFeatures::scrollAnchoringEnabled() &&
       scrollType != AnchoringScroll && scrollType != ClampingScroll)
     scrollAnchor()->clear();
 }
 
 IntSize PaintLayerScrollableArea::scrollOffsetInt() const {
   return flooredIntSize(m_scrollOffset);
 }
@@ skipping 1492 matching lines @@
 
 void PaintLayerScrollableArea::DelayScrollOffsetClampScope::
     clampScrollableAreas() {
   for (auto& scrollableArea : *s_needsClamp)
     scrollableArea->clampScrollOffsetsAfterLayout();
   delete s_needsClamp;
   s_needsClamp = nullptr;
 }
 
 }  // namespace blink