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 c23d25157f7d92edcfad150b9fde72acbf523b45..724dd118bb29d97a78a9082a668798340159f56c 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&);
-  void mouseExitedScrollbar(Scrollbar&);
+  virtual void mouseEnteredScrollbar(Scrollbar&);
+  virtual void mouseExitedScrollbar(Scrollbar&);
   void mouseCapturedScrollbar();
   void mouseReleasedScrollbar();
   void contentAreaDidShow() const;
@@ -123,10 +123,10 @@ 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);
   }
@@ -167,10 +167,10 @@ 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.
@@ -200,6 +200,10 @@ 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
@@ -221,6 +225,9 @@ 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;
@@ -362,6 +369,8 @@ class PLATFORM_EXPORT ScrollableArea : public GarbageCollectedMixin {
 
   virtual ScrollAnchor* scrollAnchor() { return nullptr; }
 
+  virtual void scrollbarVisibilityChanged() {}
+
  protected:
   ScrollableArea();
 
@@ -391,7 +400,6 @@ class PLATFORM_EXPORT ScrollableArea : public GarbageCollectedMixin {
     m_scrollCornerNeedsPaintInvalidation = false;
   }
   void showOverlayScrollbars();
-  virtual void scrollbarVisibilityChanged() {}
 
  private:
   void programmaticScrollHelper(const ScrollOffset&, ScrollBehavior);