Use float for scroll offset.

third_party/WebKit/Source/core/frame/RootFrameViewport.h

Index: third_party/WebKit/Source/core/frame/RootFrameViewport.h
diff --git a/third_party/WebKit/Source/core/frame/RootFrameViewport.h b/third_party/WebKit/Source/core/frame/RootFrameViewport.h
index ca416c778653e32a6b278778fe5bcace0080027d..54d69c5fea50a6e9bcf3baa63f2afe2aa6cc7ef1 100644
--- a/third_party/WebKit/Source/core/frame/RootFrameViewport.h
+++ b/third_party/WebKit/Source/core/frame/RootFrameViewport.h
@@ -47,22 +47,20 @@ class CORE_EXPORT RootFrameViewport final
   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;
@@ -74,12 +72,12 @@ class CORE_EXPORT RootFrameViewport final
   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;
@@ -108,9 +106,9 @@ class CORE_EXPORT RootFrameViewport final
 
   enum ViewportToScrollFirst { VisualViewport, LayoutViewport };
 
-  DoublePoint scrollOffsetFromScrollAnimators() const;
+  ScrollOffset scrollOffsetFromScrollAnimators() const;
 
-  void distributeScrollBetweenViewports(const DoublePoint&,
+  void distributeScrollBetweenViewports(const ScrollOffset&,
                                         ScrollType,
                                         ScrollBehavior,
                                         ViewportToScrollFirst);