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 2de87e1c4717c03d7d404e07f1f2173a8066f0e4..c6235e86395128d1cd42dd6b96851e54bc7ace61 100644
--- a/third_party/WebKit/Source/platform/scroll/ScrollableArea.h
+++ b/third_party/WebKit/Source/platform/scroll/ScrollableArea.h
@@ -109,8 +109,8 @@ 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;
 
@@ -121,10 +121,10 @@ 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);
   }
@@ -165,10 +165,10 @@ 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.
@@ -198,6 +198,10 @@ class PLATFORM_EXPORT ScrollableArea : public GarbageCollectedMixin {
   virtual Scrollbar* horizontalScrollbar() const { return nullptr; }
   virtual Scrollbar* verticalScrollbar() const { return nullptr; }
 
+  // Called to update the scrollbars to accurately reflect the state of the
+  // view.
+  virtual void updateScrollbars(){};
+
   // scrollPosition is the location of the top/left of the scroll viewport in
   // the coordinate system defined by the top/left of the overflow rect.
   // scrollOffset is the offset of the scroll viewport from its position when
@@ -219,6 +223,9 @@ 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;