MainFrame scrollbars should work with RFV instead of FV

third_party/WebKit/Source/core/frame/VisualViewport.cpp

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 278 matching lines @@
   }
 
   if (!valuesChanged)
     return false;
 
   InspectorInstrumentation::didUpdateLayout(mainFrame());
   mainFrame()->loader().saveScrollState();
 
   clampToBoundaries();
 
+  mainFrame()->view()->updateScrollbars();

[bokan, 2016/10/31 15:25:09]

VisualViewport shouldn't be talking to FrameView, this should happen though the
RFV. There's already VisualViewport::notifyRootFrameViewport, just call into
FrameView::updateScrollbars from RootFrameViewport::didUpdateVisualViewport

[ymalik, 2016/11/03 18:49:12]

Yes you're right.

I have RFV::didUpdateVisualViewport calling updateScrollbars now.

+
   return true;
 }
 
 bool VisualViewport::magnifyScaleAroundAnchor(float magnifyDelta,
                                               const FloatPoint& anchor) {
   const float oldPageScale = scale();
   const float newPageScale =
       frameHost().chromeClient().clampPageScaleFactorToLimits(magnifyDelta *
                                                               oldPageScale);
   if (newPageScale == oldPageScale)
@@ skipping 515 matching lines @@
   } else if (graphicsLayer == m_rootTransformLayer.get()) {
     name = "Root Transform Layer";
   } else {
     ASSERT_NOT_REACHED();
   }
 
   return name;
 }
 
 }  // namespace blink