Use float for scroll offset.

third_party/WebKit/Source/core/layout/LayoutView.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
  *
  * 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 319 matching lines @@
     mode &= ~IsFixed;
   }
 
   if (ancestor == this)
     return;
 
   if (mode & TraverseDocumentBoundaries) {
     LayoutPartItem parentDocLayoutItem = frame()->ownerLayoutItem();
     if (!parentDocLayoutItem.isNull()) {
       if (!(mode & InputIsInFrameCoordinates)) {
-        transformState.move(-frame()->view()->scrollOffset());
+        transformState.move(LayoutSize(-frame()->view()->scrollOffset()));
       } else {
         // The flag applies to immediate LayoutView only.
         mode &= ~InputIsInFrameCoordinates;
       }
 
       transformState.move(parentDocLayoutItem.contentBoxOffset());
 
       parentDocLayoutItem.mapLocalToAncestor(ancestor, transformState, mode);
     }
   }
 }
 
 const LayoutObject* LayoutView::pushMappingToContainer(
     const LayoutBoxModelObject* ancestorToStopAt,
     LayoutGeometryMap& geometryMap) const {
   LayoutSize offsetForFixedPosition;
   LayoutSize offset;
   LayoutObject* container = nullptr;
 
   if (m_frameView) {
-    offsetForFixedPosition =
-        LayoutSize(LayoutSize(m_frameView->scrollOffset()));
+    offsetForFixedPosition = LayoutSize(m_frameView->scrollOffset());
     if (hasOverflowClip())
       offsetForFixedPosition = LayoutSize(scrolledContentOffset());
   }
 
   if (geometryMap.getMapCoordinatesFlags() & TraverseDocumentBoundaries) {
     if (LayoutPart* parentDocLayoutObject = toLayoutPart(
             LayoutAPIShim::layoutObjectFrom(frame()->ownerLayoutItem()))) {
       offset = -LayoutSize(m_frameView->scrollOffset());
       offset += parentDocLayoutObject->contentBoxOffset();
       container = parentDocLayoutObject;
@@ skipping 23 matching lines @@
     return;
 
   if (mode & TraverseDocumentBoundaries) {
     if (LayoutPart* parentDocLayoutObject = toLayoutPart(
             LayoutAPIShim::layoutObjectFrom(frame()->ownerLayoutItem()))) {
       // A LayoutView is a containing block for fixed-position elements, so don't carry this state across frames.
       parentDocLayoutObject->mapAncestorToLocal(ancestor, transformState,
                                                 mode & ~IsFixed);
 
       transformState.move(parentDocLayoutObject->contentBoxOffset());
-      transformState.move(-frame()->view()->scrollOffset());
+      transformState.move(LayoutSize(-frame()->view()->scrollOffset()));
     }
   } else {
     ASSERT(!ancestor);
   }
 
   if (mode & IsFixed)
-    transformState.move(frame()->view()->scrollOffset());
+    transformState.move(LayoutSize(frame()->view()->scrollOffset()));
 }
 
 void LayoutView::computeSelfHitTestRects(Vector<LayoutRect>& rects,
                                          const LayoutPoint&) const {
   // Record the entire size of the contents of the frame. Note that we don't just
   // use the viewport size (containing block) here because we want to ensure this includes
   // all children (so we can avoid walking them explicitly).
   rects.append(
       LayoutRect(LayoutPoint::zero(), LayoutSize(frameView()->contentsSize())));
 }
@@ skipping 611 matching lines @@
   if (block)
     block->adjustChildDebugRect(rect);
 
   rect.setWidth(LayoutUnit(viewWidth(IncludeScrollbars)));
   rect.setHeight(LayoutUnit(viewHeight(IncludeScrollbars)));
 
   return rect;
 }
 
 }  // namespace blink