Use float for scroll offset.

third_party/WebKit/Source/core/dom/ElementRareData.h

 /*
  * Copyright (C) 2008, 2009, 2010 Apple Inc. All rights reserved.
  * Copyright (C) 2008 David Smith <catfish.man@gmail.com>
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
@@ skipping 96 matching lines @@
   }
 
   DatasetDOMStringMap* dataset() const { return m_dataset.get(); }
   void setDataset(DatasetDOMStringMap* dataset) { m_dataset = dataset; }
 
   LayoutSize minimumSizeForResizing() const { return m_minimumSizeForResizing; }
   void setMinimumSizeForResizing(LayoutSize size) {
     m_minimumSizeForResizing = size;
   }
 
-  IntSize savedLayerScrollOffset() const { return m_savedLayerScrollOffset; }
-  void setSavedLayerScrollOffset(IntSize size) {
-    m_savedLayerScrollOffset = size;
+  ScrollOffset savedLayerScrollOffset() const {
+    return m_savedLayerScrollOffset;
+  }
+  void setSavedLayerScrollOffset(ScrollOffset offset) {
+    m_savedLayerScrollOffset = offset;
   }
 
   ElementAnimations* elementAnimations() { return m_elementAnimations.get(); }
   void setElementAnimations(ElementAnimations* elementAnimations) {
     m_elementAnimations = elementAnimations;
   }
 
   bool hasPseudoElements() const;
   void clearPseudoElements();
 
@@ skipping 42 matching lines @@
 
   DECLARE_TRACE_WRAPPERS_AFTER_DISPATCH();
 
  private:
   CompositorProxiedPropertySet& ensureCompositorProxiedPropertySet();
   void clearCompositorProxiedPropertySet() { m_proxiedProperties = nullptr; }
 
   short m_tabindex;
 
   LayoutSize m_minimumSizeForResizing;
-  IntSize m_savedLayerScrollOffset;
+  ScrollOffset m_savedLayerScrollOffset;
 
   Member<DatasetDOMStringMap> m_dataset;
   Member<ElementShadow> m_shadow;
   Member<ClassList> m_classList;
   Member<NamedNodeMap> m_attributeMap;
   Member<AttrNodeList> m_attrNodeList;
   Member<InlineCSSStyleDeclaration> m_cssomWrapper;
   Member<InlineStylePropertyMap> m_cssomMapWrapper;
   std::unique_ptr<CompositorProxiedPropertySet> m_proxiedProperties;
 
@@ skipping 66 matching lines @@
 inline CompositorProxiedPropertySet&
 ElementRareData::ensureCompositorProxiedPropertySet() {
   if (!m_proxiedProperties)
     m_proxiedProperties = CompositorProxiedPropertySet::create();
   return *m_proxiedProperties;
 }
 
 }  // namespace blink
 
 #endif  // ElementRareData_h