MainFrame scrollbars should work with RFV instead of FV

third_party/WebKit/Source/platform/scroll/ScrollableArea.h

Index: third_party/WebKit/Source/platform/scroll/ScrollableArea.h
diff --git a/third_party/WebKit/Source/platform/scroll/ScrollableArea.h b/third_party/WebKit/Source/platform/scroll/ScrollableArea.h
index 17802ed6a3ff26305b8a23f95e16c7a16e7fe54c..fff34cde0aef61e53653e1796d2e16d5c38cbf0a 100644
--- a/third_party/WebKit/Source/platform/scroll/ScrollableArea.h
+++ b/third_party/WebKit/Source/platform/scroll/ScrollableArea.h
@@ -107,8 +107,8 @@ class PLATFORM_EXPORT ScrollableArea : public GarbageCollectedMixin {
   void mouseEnteredContentArea() const;
   void mouseExitedContentArea() const;
   void mouseMovedInContentArea() const;
-  void mouseEnteredScrollbar(Scrollbar&) const;
-  void mouseExitedScrollbar(Scrollbar&) const;
+  virtual void mouseEnteredScrollbar(Scrollbar&) const;
+  virtual void mouseExitedScrollbar(Scrollbar&) const;
   void contentAreaDidShow() const;
   void contentAreaDidHide() const;
 
@@ -119,10 +119,10 @@ class PLATFORM_EXPORT ScrollableArea : public GarbageCollectedMixin {
 
   virtual void contentsResized();
 
-  bool hasOverlayScrollbars() const;
+  virtual bool hasOverlayScrollbars() const;
   void setScrollbarOverlayColorTheme(ScrollbarOverlayColorTheme);
   void recalculateScrollbarOverlayColorTheme(Color);
-  ScrollbarOverlayColorTheme getScrollbarOverlayColorTheme() const {
+  virtual ScrollbarOverlayColorTheme getScrollbarOverlayColorTheme() const {
     return static_cast<ScrollbarOverlayColorTheme>(
         m_scrollbarOverlayColorTheme);
   }
@@ -163,10 +163,10 @@ class PLATFORM_EXPORT ScrollableArea : public GarbageCollectedMixin {
 
   virtual bool isActive() const = 0;
   virtual int scrollSize(ScrollbarOrientation) const = 0;
-  void setScrollbarNeedsPaintInvalidation(ScrollbarOrientation);
+  virtual void setScrollbarNeedsPaintInvalidation(ScrollbarOrientation);
   virtual bool isScrollCornerVisible() const = 0;
   virtual IntRect scrollCornerRect() const = 0;
-  void setScrollCornerNeedsPaintInvalidation();
+  virtual void setScrollCornerNeedsPaintInvalidation();
   virtual void getTickmarks(Vector<IntRect>&) const {}
 
   // Convert points and rects between the scrollbar and its containing Widget.
@@ -217,6 +217,9 @@ class PLATFORM_EXPORT ScrollableArea : public GarbageCollectedMixin {
   virtual ScrollOffset maximumScrollOffset() const {
     return ScrollOffset(maximumScrollOffsetInt());
   }
+  virtual ScrollOffset scrollAnimatorDesiredTargetOffset() const {
+    return scrollAnimator().desiredTargetOffset();
+  }
 
   virtual IntRect visibleContentRect(
       IncludeScrollbarsInRect = ExcludeScrollbars) const;