Reland of place pinch scrollbars with regular scrollbars.

Source/core/layout/compositing/DeprecatedPaintLayerCompositor.cpp

 /*
  * Copyright (C) 2009, 2010 Apple 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:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 889 matching lines @@
 }
 
 bool DeprecatedPaintLayerCompositor::requiresScrollCornerLayer() const
 {
     return m_layoutView.frameView()->isScrollCornerVisible();
 }
 
 void DeprecatedPaintLayerCompositor::updateOverflowControlsLayers()
 {
     GraphicsLayer* controlsParent = m_rootTransformLayer.get() ? m_rootTransformLayer.get() : m_overflowControlsHostLayer.get();
-    // On Mac, main frame scrollbars should always be stuck to the sides of the screen (in overscroll and in pinch-zoom), so
+    // Main frame scrollbars should always be stuck to the sides of the screen (in overscroll and in pinch-zoom), so
     // make the parent for the scrollbars be the viewport container layer.
-#if OS(MACOSX)
     if (m_layoutView.frame()->isMainFrame()) {
         VisualViewport& visualViewport = m_layoutView.frameView()->page()->frameHost().visualViewport();
         controlsParent = visualViewport.containerLayer();
     }
-#endif
 
     if (requiresHorizontalScrollbarLayer()) {
         if (!m_layerForHorizontalScrollbar) {
             m_layerForHorizontalScrollbar = GraphicsLayer::create(graphicsLayerFactory(), this);
         }
 
         if (m_layerForHorizontalScrollbar->parent() != controlsParent) {
             controlsParent->addChild(m_layerForHorizontalScrollbar.get());
 
             if (ScrollingCoordinator* scrollingCoordinator = this->scrollingCoordinator())
@@ skipping 275 matching lines @@
     } else if (graphicsLayer == m_scrollLayer.get()) {
         name = "LocalFrame Scrolling Layer";
     } else {
         ASSERT_NOT_REACHED();
     }
 
     return name;
 }
 
 } // namespace blink