Handle nested position:sticky elements correctly (compositor)

third_party/WebKit/Source/core/page/scrolling/StickyPositionScrollingConstraints.cpp

 // Copyright 2016 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.
 
 #include "core/page/scrolling/StickyPositionScrollingConstraints.h"
 
 namespace blink {
 
 FloatSize StickyPositionScrollingConstraints::computeStickyOffset(
     const FloatRect& viewportRect,
@@ skipping 62 matching lines @@
 
     boxRect.move(0, topDelta);
   }
 
   FloatSize stickyOffset = boxRect.location() - stickyBoxRect.location();
 
   m_totalStickyBoxStickyOffset = ancestorStickyBoxOffset + stickyOffset;
   m_totalContainingBlockStickyOffset =
       ancestorStickyBoxOffset + ancestorContainingBlockOffset + stickyOffset;
 
+  m_localStickyOffset = stickyOffset;
+
   return stickyOffset;
 }
 
 }  // namespace blink