Add development Blink setting for impl-side rubber-banding

Source/core/frame/FrameView.cpp

 /*
  * Copyright (C) 1998, 1999 Torben Weis <weis@kde.org>
  *                     1999 Lars Knoll <knoll@kde.org>
  *                     1999 Antti Koivisto <koivisto@kde.org>
  *                     2000 Dirk Mueller <mueller@kde.org>
  * Copyright (C) 2004, 2005, 2006, 2007, 2008 Apple Inc. All rights reserved.
  *           (C) 2006 Graham Dennis (graham.dennis@gmail.com)
  *           (C) 2006 Alexey Proskuryakov (ap@nypop.com)
  * Copyright (C) 2009 Google Inc. All rights reserved.
  *
@@ skipping 1655 matching lines @@
         return false;
 
     // If the main thread updates the scroll position for this FrameView, we should return
     // ScrollAnimator::isRubberBandInProgress().
     if (ScrollAnimator* scrollAnimator = existingScrollAnimator())
         return scrollAnimator->isRubberBandInProgress();
 
     return false;
 }
 
+bool FrameView::rubberBandingOnCompositorThread() const
+{
+    return m_frame->settings()->rubberBandingOnCompositorThread();
+}
+
 HostWindow* FrameView::hostWindow() const
 {
     Page* page = frame().page();
     if (!page)
         return 0;
     return &page->chrome();
 }
 
 void FrameView::contentRectangleForPaintInvalidation(const IntRect& rect)
 {
@@ skipping 2271 matching lines @@
         return;
 
     ScrollableArea::setScrollOrigin(origin);
 
     // Update if the scroll origin changes, since our position will be different if the content size did not change.
     if (updatePositionAtAll && updatePositionSynchronously)
         updateScrollbars(scrollOffsetDouble());
 }
 
 } // namespace blink