Use float for scroll offset.

third_party/WebKit/Source/core/frame/RootFrameViewport.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 RootFrameViewport_h
 #define RootFrameViewport_h
 
 #include "core/CoreExport.h"
 #include "platform/scroll/ScrollableArea.h"
 
@@ skipping 29 matching lines @@
 
   // Convert from the root content document's coordinate space, into the
   // coordinate space of the layout viewport's content. In the normal case,
   // this will be a no-op since the root FrameView is the layout viewport and
   // so the root content is the layout viewport's content but if the page
   // sets a custom root scroller via document.rootScroller, another element
   // may be the layout viewport.
   LayoutRect rootContentsToLayoutViewportContents(FrameView& rootFrameView,
                                                   const LayoutRect&) const;
 
-  void restoreToAnchor(const DoublePoint&);
+  void restoreToAnchor(const ScrollOffset&);
 
   // Callback whenever the visual viewport changes scroll position or scale.
   void didUpdateVisualViewport();
 
   // ScrollableArea Implementation
   bool isRootFrameViewport() const override { return true; }
-  void setScrollPosition(const DoublePoint&,
-                         ScrollType,
-                         ScrollBehavior = ScrollBehaviorInstant) override;
+  void setScrollOffset(const ScrollOffset&,
+                       ScrollType,
+                       ScrollBehavior = ScrollBehaviorInstant) override;
   LayoutRect scrollIntoView(const LayoutRect& rectInContent,
                             const ScrollAlignment& alignX,
                             const ScrollAlignment& alignY,
                             ScrollType = ProgrammaticScroll) override;
-  DoubleRect visibleContentRectDouble(
-      IncludeScrollbarsInRect = ExcludeScrollbars) const override;
   IntRect visibleContentRect(
       IncludeScrollbarsInRect = ExcludeScrollbars) const override;
   bool shouldUseIntegerScrollOffset() const override;
   LayoutRect visualRectForScrollbarParts() const override {
     ASSERT_NOT_REACHED();
     return LayoutRect();
   }
   bool isActive() const override;
   int scrollSize(ScrollbarOrientation) const override;
   bool isScrollCornerVisible() const override;
   IntRect scrollCornerRect() const override;
-  void setScrollOffset(const DoublePoint&, ScrollType) override;
-  IntPoint scrollPosition() const override;
-  DoublePoint scrollPositionDouble() const override;
-  IntPoint minimumScrollPosition() const override;
-  IntPoint maximumScrollPosition() const override;
-  DoublePoint maximumScrollPositionDouble() const override;
+  void updateScrollOffset(const ScrollOffset&, ScrollType) override;
+  IntSize scrollOffsetInt() const override;
+  ScrollOffset scrollOffset() const override;
+  IntSize minimumScrollOffsetInt() const override;
+  IntSize maximumScrollOffsetInt() const override;
+  ScrollOffset maximumScrollOffset() const override;
   IntSize contentsSize() const override;
   bool scrollbarsCanBeActive() const override;
   IntRect scrollableAreaBoundingBox() const override;
   bool userInputScrollable(ScrollbarOrientation) const override;
   bool shouldPlaceVerticalScrollbarOnLeft() const override;
   void scrollControlWasSetNeedsPaintInvalidation() override;
   GraphicsLayer* layerForContainer() const override;
   GraphicsLayer* layerForScrolling() const override;
   GraphicsLayer* layerForHorizontalScrollbar() const override;
   GraphicsLayer* layerForVerticalScrollbar() const override;
   GraphicsLayer* layerForScrollCorner() const override;
   ScrollResult userScroll(ScrollGranularity, const FloatSize&) override;
   bool scrollAnimatorEnabled() const override;
   HostWindow* getHostWindow() const override;
   void serviceScrollAnimations(double) override;
   void updateCompositorScrollAnimations() override;
   void cancelProgrammaticScrollAnimation() override;
   ScrollBehavior scrollBehaviorStyle() const override;
   Widget* getWidget() override;
   void clearScrollAnimators() override;
   LayoutBox* layoutBox() const override;
 
  private:
   RootFrameViewport(ScrollableArea& visualViewport,
                     ScrollableArea& layoutViewport);
 
   enum ViewportToScrollFirst { VisualViewport, LayoutViewport };
 
-  DoublePoint scrollOffsetFromScrollAnimators() const;
+  ScrollOffset scrollOffsetFromScrollAnimators() const;
 
-  void distributeScrollBetweenViewports(const DoublePoint&,
+  void distributeScrollBetweenViewports(const ScrollOffset&,
                                         ScrollType,
                                         ScrollBehavior,
                                         ViewportToScrollFirst);
 
   // If either of the layout or visual viewports are scrolled explicitly (i.e.
   // not through this class), their updated offset will not be reflected in this
   // class' animator so use this method to pull updated values when necessary.
   void updateScrollAnimator();
 
   ScrollableArea& visualViewport() const {
     ASSERT(m_visualViewport);
     return *m_visualViewport;
   }
 
   Member<ScrollableArea> m_visualViewport;
   Member<ScrollableArea> m_layoutViewport;
 };
 
 DEFINE_TYPE_CASTS(RootFrameViewport,
                   ScrollableArea,
                   scrollableArea,
                   scrollableArea->isRootFrameViewport(),
                   scrollableArea.isRootFrameViewport());
 
 }  // namespace blink
 
 #endif  // RootFrameViewport_h